Company: SNY
Filing Date: 2025-10-27
Form Type: 424B5
Source: 0001193125-25-250786
Chunk: 31

Company: Sanofi
Filing Date: 2025-10-27
Form: 424B5
Chunk 31
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 Notes are registered at the close of business
on and , as applicable (which are the regular record dates), immediately preceding the related Interest Payment Date.

We will pay interest on the Fixed Rate Notes on the Interest Payment Dates stated above and at maturity. Each payment of interest due on an
Interest Payment Date or at maturity or redemption will include interest accrued from and including the last date to which interest has been paid or made available for payment, or from the issue date, if none has been paid or made available for
payment, to but excluding the relevant payment date. We will compute interest on the Notes on the basis of a 360-day year of twelve 30-day months.

If any payment is due on the Fixed Rate Notes on a day that is not a business day, we will make the payment on the day that is the next
business day. Payments postponed to the next business day in this situation will be treated under the Indenture as if they were made on the original due date. Postponements of this kind will not result in a default under the Fixed Rate Notes or the
Indenture, and no interest will accrue on the postponed amount from the original due date to the next day that is a business day.

Floating Rate Notes

The 20 Floating Rate Notes and the 20 Floating Rate Notes will mature at par on ,
20 and , 20 , respectively.

The Floating Rate Notes will bear interest
at a floating rate, reset quarterly on each Floating Rate Interest Payment Date (as defined below), equal to Compounded SOFR (as defined below), plus %. In no event will the interest on the Floating Rate Notes be less than zero.
Interest on the Floating Rate Notes will be payable quarterly in arrears on , , and of each year, beginning , 2026, and at the maturity or redemption
date (each a “Floating Rate Interest Payment Date”). With respect to the Floating Rate Notes, an “interest period” means the period from and including a Floating Rate Interest Payment Date (or, in the case of the initial
interest period, from and including the settlement date of the Floating Rate Notes) to, but excluding, the immediately succeeding Floating Rate Interest Payment Date (such succeeding Floating Rate Interest Payment Date, the “Latter Floating
Rate Interest Payment Date”); provided that, if a Floating Rate Interest Payment Date, other than the maturity date or the date of redemption or repayment, falls on a day that is not a business day, the Floating Rate Interest Payment will be
postpon