Sworn affidavit for green card application (I-130, I-145)?

No. Typically the document needs to be sworn to in person. They can write the affidavits in English, have them notarized by a French notary (or some equivalent to a notary in the US). They can scan you the documents and you can print them and take the printed copy to the interview, but typically you want to present originals of foreign documents when possible; if it's not possible to take the originals, copies are ok. You can also have other family/friends in the US write affidavits for you and your spouse and also submit those originals. Typically the sworn statements act as further evidence that your relationship is bona fide, so even if not from family, they still serve the same purpose. Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.