Company: SNY
Filing Date: 2025-10-29
Form Type: 424B5
Source: 0001193125-25-255563
Chunk: 31

Company: Sanofi
Filing Date: 2025-10-29
Form: 424B5
Chunk 31
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 in this prospectus supplement. If floating rate notes are specified in the pricing term sheet, the interest provisions will be specified therein. The below provisions apply to fixed rate notes only.

However, as indicated in the “Description of Debt Securities We May Offer,” the indenture to be entered into between us and Deutsche Bank Trust Company Americas will contain the full legal text governing the matters summarized in the referenced section “Description of Debt Securities We May Offer” of the attached prospectus and in this section, and such sections are subject to and qualified in their entirety by reference to all the provisions of the indenture. See the “Description of Debt Securities We May Offer” for more information.

General

We will offer the notes under an
indenture between the Issuer and Deutsche Bank Trust Company Americas, as trustee, to be dated as of November 3, 2025 (the “Indenture”). The notes will be issued only in fully registered form without coupons in minimum denominations
of U.S.$2,000 and integral multiples of U.S.$1,000 in excess thereof. The notes will be unsecured and unsubordinated and therefore will rank equally with all of our other existing and future unsecured and unsubordinated debt.

The notes will be governed by and construed in accordance with the laws of the State of New York.

As used herein, “business day” means (i) in respect of any payment due on the Notes, each Monday, Tuesday, Wednesday,
Thursday and Friday which is not a day on which banking or trust institutions in New York or London are authorized generally or obligated by law, regulation or executive order to close; and (ii) in respect of any other matter, including any
other notice period, set forth herein or in the attached prospectus or in the Indenture, each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking or trust institutions in New York or Paris are authorized generally or
obligated by law, regulation or executive order to close.

Principal, Interest and Maturity

For the purposes of this section, the notes offered pursuant to this prospectus supplement are (i) the $500,000,000 floating rate notes
due 2027 (the “2027 floating rate notes”), (ii) the $500,000,000 floating rate notes due 2028 (the “2028 floating rate notes” and, together with the 2027 floating rate notes, the “Floating Rate Notes”), (iii) the
$400,000