BofA MERRILL LYNCH HEALTHCARE CONFERENCE Dr. Paul Chew

U.S. Chief Science Officer / Chief Medical Officer, SVP

May 15, 2012

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Forward Looking Statements

This presentation contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future financial results, events, operations, services, product development and potential, and statements regarding future performance. Forward-looking statements are generally identified by the words "expects", "anticipates", "believes", "intends", "estimates", "plans" and similar expressions. Although Sanofi's management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Sanofi, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include among other things, the uncertainties inherent in research and development, future clinical data and analysis, including post marketing, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug, device or biological application that may be filed for any such product candidates as well as their decisions regarding labeling and other matters that could affect the availability or commercial potential of such product candidates, the absence of guarantee that the product candidates if approved will be commercially successful, the future approval and commercial success of therapeutic alternatives, the Group's ability to benefit from external growth opportunities, trends in exchange rates and prevailing interest rates, the impact of cost containment policies and subsequent changes thereto, the average number of shares outstanding as well as those discussed or identified in the public filings with the SEC and the AMF made by Sanofi, including those listed under "Risk Factors" and "Cautionary Statement Regarding Forward-Looking Statements" in Sanofi's annual report on Form 20-F for the year ended December 31, 2011. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements.

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€1.66

Q1 2011 Q1 2012

Total Sales (€m)

2012 - A Good Start to the Year

€7,779m

Q1 2011 Q1 2012

Business EPS (€)

€1.85

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€8,511m

+7.2% at CER

+7.0% at CER

Growth Platforms Accounted for 63.2% of Sales in Q1 2012

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Growth is at CER (Constant Exchange Rates)(1) With Genzyme pro forma in Q1 2011, Emerging Market sales grew by 5.6%, and by 7.9% excluding vaccines(2) New Genzyme perimeter include Rare Diseases and Multiple Sclerosis franchises(3) Change on a constant structure basis and at constant exchange rates(4) Multaq®, Jevtana®, and Mozobil®

+14.4% +14.4%

+11.4%+11.4%

-0.2%-0.2%

-5.4%-5.4%

+13.7%(3) +13.7%(3)

Innovative Products(4) €139m +6.3%(3)+6.3%(3)

+9.9%(1) +9.9%(1)

Consumer Health Care €805m

Diabetes Solutions €1,311m

Vaccines €617m

Animal Health €578m

Emerging Markets €2,624m

New Genzyme(2) €400m

Growth at CER

Executing Successful Strategy to Reposition Sanofi

Deliver sustainable growth

and generate improved

shareholder returnsAdapt structure for future challenges and opportunities3

Pursue external growth opportunities2

Increase innovation in R&D1

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Executing our R&D Strategy

GlobalR&D

Goals

An efficient global R&D organization Maximize synergies and convergence around Hub modelExploit economies of scale Improve R&D cost structure

Focus on high-value projects Execute on late-stage projectsMedical value and translational feasibility to guide early-stage

portfolio prioritization

Establish new models of external innovationEnhance the value of external opportunities and partnershipsCreate open and creative model of pharma-biotech partnership

e.g. Warp Drive Bio

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Focusing on Delivering a Promising Development Portfolio

Achieve Regulatory Milestones

• Lemtrada™• Aubagio™• Lyxumia® (1)

• Zaltrap™(2)

• Semuloparin• Kynamro™ (3)

Next Wave of Late-Stage Projects

• New glargine formulation• Glargine-lixisenatide combo• Dengue vaccine• Eliglustat• Anti-PCSK-9 mAb

EU/U.S.

EU

EU/U.S.

EU/U.S.

EU/U.S.

• Otamixaban• Sarilumab• JAK-2 inhibitor• Iniparib• Ombrabulin

Short-term opportunities

Mid-term opportunities

Submitted

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Lemtrada™, Aubagio™, Lyxumia®, Zaltrap™, and Kynamro™ are registered trade names submitted to health authorities for investigational agents(1) In-licensed from Zealand Pharma A/S(2) Partnership with Regeneron(3) In-licensed from Isis Pharmaceuticals

Efficacy with manageable safety

Convenience & efficacy

Early MS/CIS(1) RRMS(2) and early active MS

RMS(3) severe/ highly active

Emergence of a Franchise Addressing the Full Spectrum of Patient Needs in Multiple Sclerosis

Lemtrada™

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Aubagio®

Convenience & safety

Rebif®

Lemtrada™

Aubagio™

CIS – Clinically Isolated Syndrome, TOPIC Phase III study presently ongoing RRMS – Relapse Remitting Multiple SclerosisRMS – Relapsing Multiple Sclerosis

Genzyme - MS

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9Coles A ECTRIMS 2011; platform presentation

CARE-MS I - Strong Effect on Relapse

Proportion of Relapse-Free Patients at Year 2

59%

78%

Lemtrada™ 12 mg/day Rebif®

HR 0.45 P<0.001

CARE-MS II - Reversing Disability in Some Patients

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Mean EDSS Change from Baseline

p<0.0001

0.24 p=0.0064

‒0.17 p=0.0044

Rebif®Lemtrada™ 12 mg/day

EDSS – Expanded Disability Status ScoreCohen J AAN 2012; platform presentation

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Aubagi A Once-Daily Oral Therapy with Comparable Efficacy to Injectable Interferon

●

Efficacy demonstrated in TEMSO on both Relapse Rate and Disability Progression at 14mg

●

No superiority vs. Rebif® in TENERE but lower rate of TEAE- related discontinuation

●

Manageable safety profile with up to 10 years of follow-up

(1) Adjusted for Expanded Disability Status Scale score strata at baseline and takes duration of treatment into account.TEAE – Treatment Emergent Adverse Events, ACTRIMS - Americas Committee for Treatment and Research in Multiple SclerosisENS – European Neurological Society, ARR – Annualized Relapse Rate, RRR – Relative risk reduction, HRR – Hazard ratio reduction

TEMSO: Reduction in Adjusted(1) ARR

RRR: 31.2%p=0.0002

RRR: 31.5%p=0.0005

0%

20%

10%

HRR: 23.7%p=ns

HRR: 29.8%p=0.0279

30%PlaceboT. 7 mgT. 14 mg

Week

TEMSO: Reduction in Disability Progression (%)

Genzyme - MS

0 0,1 0,2 0,3 0,4 0,5 0,6

T. 14 mg

T. 7 mg

Placebo

0 12 24 36 48 60 72 84 96 108

A GLP-1 Agonist with Unique Post-Prandial Effect and One Step Titration

MonoMono Japan

Drug naïve patients

Placebo-controlledin OAD failure

M (metformin)

F1 (metformin)

M Asia (metformin)

S (sulfonylurea)

P (pioglitazone)

X vs. exenatideActive-controlled

L

L AsiaPlacebo-controlled on

top of basal insulin

Placebo-controlled Secondary prevention

Cardiovascular Outcomes Study

Reported

Lixisenatide was in-licensed from Zealand Pharma A/S. Lyxumia® is the intended trademark for lixisenatide. Lixisenatide is currently not approved or licensed anywhere in the world. 12

Duo 1 (Lantus®)

Consistent GLP-1 class effects of A1c reduction and weight loss

Pronounced effect on post-prandial glucose

Favorable safety profile with low risk of hypoglycemic events

OD injection, simple 1 step to maintenance dose, 1 pen per dose

Lyxumia® Profile

®Diabetes

Ongoing

●

3 positive GetGoal trials with Lyxumia® on top of basal insulin

●

A1c target and PPG control achieved when used on top of Lantus® in GetGoal-Duo 1(3)

●

Development of injection device for variable Lantus® dose with fixed Lyxumia® dose on track for Phase III initiation early 2013

T2D Patients Treated with Basal Insulin(1)

(worldwide)

On basal insulin On basal insulinwith controlled fasting

glucose controlbut A1c >7%

4 million

T2D – Type 2 Diabetes, A1C – Glycated hemoglobin, PPG – Post Prandial Glucose(1) Adapted from IMS data(2) Includes all types of basal insulins(3) Top line results press release (6 Dec 2011) – Full results expected at a forthcoming scientific meeting

Optimal Complementary Pharmacological Profile with Basal Insulins

Diabetes®

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4 million on other

basal insulins(2)

4 million on Lantus®

New Glargine Formulation with Unique Pharmacokinetics

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New Insulin Glargine Formulation Depot formation after subcutaneous injection

PK/PD – Pharmacokinetic/pharmacodynamicT2D – Type 2 Diabetes

Schematic illustration

●

New glargine formulation provides

●

Unique flat PK/PD profile

●

Lower injection volume

●

Phase III trials recently initiated in T2D high dose insulin users

●

Targeting ~1,600 patients

Diabetes

Lantus® New Glargine Formulation

Strengthening our Portfolio of Oncology Drugs

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●

A novel VEGF trap acting on multiple angiogenic targets

●

Previously treated metastatic colorectal cancer

●

VELOUR: Significant improvement in Overall Survival

●

Manageable safety profile consistent with previous studies

Zaltrap® aflibercept

Mulsevo™ is a registered trade name submitted to health authorities for an investigational agentNSCLC – Non Small Cell Lung Cancer VTE – Venous Thrombo Embolism (includes Deep Venous Thrombosis and Pulmonary Embolism)

Oncology

●

Only ultra-LMWH effective in reducing VTE risk reduction in chemo-treated cancer patients

●

Without impact on major bleeding incidence

●

Treatment effect consistent across solid tumor types, stages and geographical regions

™

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Kynamro™: Targeting Rare Familial Hypercholesterolemias

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(1) Patients for HoFH and Severe FH in US and EU marketsHoFH – Homozygous Familial HypercholesterolemiaSevere FH – Severe Familial Hypercholesterolemia = treated LDL-C CHD – Coronary Heart DiseaseHeFH – Heterozygous familial hypercholesterolemiaISR – Injection Site ReactionsFLS – Flu Like Symptoms

●

Four Phase III trials conducted in severe forms of hypercholesterolemia●

Sustained reduction in apo B production resulting in significant decreases in LDL-C and Lp(a) when added to a regimen of maximally tolerated statin dose and other lipid lowering therapies

●

Adverse reactions include ISRs, FLS, and elevations in liver transaminases and fat●

Liver fat stabilized or decreased in some patients with treatment beyond 12 months

HeFH: 1 million patients

HoFH Severe FH

Understanding Rarity

~40,000 patients(1)

On statins: 60 million patients

PCSK9 mAb: First in Class and Addressing Unmet Needs in Hypercholesterolemia

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LDL-C Change from baseline (Phase II)(2,4,5)

CHD – Coronary Heart Disease(1) Cohen JC. N Engl J Med 2006;354(12):1264-72(2) McKenney, et al JACC published online March 28 2012(3) Roth et al JACC Volume 59, Issue 13, Supplement, 27 March 2012, E1620(4) Patients with primary hypercholesterolemia receiving stable atorvastatin therapy; change from baseline to week 12(5) LS mean (SE), using LOCF method* P<0.0001 for % change SAR236553 vs. placebo

Metabolic Disorders

●

Landmark study demonstrated that when PCSK9 is disabled, cholesterol and risk of CHD are greatly lowered(1)

●

Phase II data(2)(3)

●

Significantly reduced mean LDL-C by 40% to 72% over 8 to 12 weeks in patients with elevated LDL-C in patients on stable dose of statins

●

Generally safe and well tolerated

●

Phase III targeted to start Q2 2012

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Eliglustat: a Novel Oral Therapy in Gaucher Disease(1)

●

Potent, novel substrate inhibitor

●

Convenience of oral therapy ●

Eliminating challenges of infusing patients

●

Clinical profile expected to be similar to Cerezyme®

●

4-year Phase II data at WORLD congress in February 2012

●

Phase III trials fully recruited

(1) Investigational drug (2) Patient from Phase II clinical trialWORLD – World Organization of Research on Lysosomal Diseases

December 2006pre-treatment (18 years)

December 20093 years post treatment (21 years)(2)

Genzyme - Rare Diseases

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Eliglustat Clinical Data Comparable to Cerezyme®

Platelets +95%

Hemoglobin +2.3 g/dL

-4

-2

0

2

4

Hb Change from Baseline

(g/dL)

-100%

-50%

0%

50%

100%

Mean % Change

from Baseline

Liver -28%

Spleen -63%

Year 1 Year 2 Year 3 Year 4Baseline

(1) Cerezyme® Registry Data on File – Upper and Lower 95% Confidence Interval around Mean

Eliglustat Phase 2 Trial Results: Treatment Changes to 4 Years(1)

Cerezyme® Range

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Dengue Vaccine: Addressing a Growing Global Threat

Ambitious R&D Program

●

Global Phase III program (43,000 individuals)

●

1st efficacy results expected by end of 2012

●

First submissions planned in 2013

Significant Disease Burden

●

Estimated 220m dengue infections worldwide per year

●

2m cases of Hemorrhagic Fever

●

>500,000 hospitalizations and >20,000 deaths / year

●

Dengue: a public health priority in Asia and Latin America

Vaccines

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Rare Diseases & MS

DiabetesOncologyOther Pharma

Ophthalmology

Vaccines

Eighteen Potential New Launches over 2012-2015

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Kynamro™ (mipomersen)

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18

Lemtrada™ (alemtuzumab)

Aubagio™ (teriflunomide)

Lyxumia®

(lixisenatide)

Zaltrap™ (aflibercept)

semuloparin Hexaxim®

ombrabulin

Dengue vaccine

eliglustat

SAR302503 (JAK-2 inhibitor)

otamixaban

DTP-HepB- Polio-Hib

FOV1101 (prednisporin)

SAR236553 anti-PCSK-9 mAb

iniparib

2012 2013 2014 2015

Cumulative Number of Projects Pharmaceuticals (excluding LCM) and Vaccines

Fluzone® QIV IM

Quadracel®

Note: Scope includes pharmaceuticals NMEs (excluding LCM – Life cycle management) and vaccines. Only first launches in a given market are mentioned.21

Key R&D Milestones for the Remainder of 2012

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Lemtrada™, Aubagio™ and Lyxumia® are registered trade names submitted to health authorities for investigational agents

2012

Expected Regulatory Submissions Q2 Q3 Q4●

Lemtrada™ (alemtuzumab) in RMS(1) in the U.S. and EU

●

Lyxumia® (lixisenatide) in Type 2 diabetes in the U.S.(2)

Expected Headline Data Releases

●

Lantus® - ORIGIN study results

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Lantus® - Retrospective cohort studies results

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Aubagio™ (teriflunomide) – TOWER headline Phase III results in RMS

●

Dengue vaccine - Phase IIb efficacy results

Expected Phase III Study Initiations

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Anti-PCSK-9 mAb - Phase III program in hypercholesterolemia

●

Sarilumab (Anti-IL-6R mAb) - Second Phase III trial

(1) RMS: Relapsing Forms of Multiple Sclerosis(2) Partnership with Zealand Pharma(3) Mid year 2012

(3)

Continued Execution of Strategy Expected to Deliver Sustainable Growth 2012-2015

2012-2015 Sales CAGR

Diversified sources of growth

Scale in businesses with significant barriers to entry

Low small molecule patent exposure in mature markets(1)

Large Emerging Markets presence(2)

Potential new product launches(3)

Operating margin evolution

2012-2015 Business EPS CAGR

Increased dividend payout ratio(4)

(1) 2012 sales from chemical products exposed to patent expiry in the U.S., Japan and Western Europe over 2012 -2015(2) Based on 2015 internal estimates(3) Over 2012-2015(4) Dividend paid in 2014

~6%

50% of 2013 results

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38-40%

Rebounding

> Sales CAGR

At least 5%

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