An American in Provence

Getting legally married in France is tricky enough for a French citizen, even harder for foreigners. Many couples opt for just a civil ceremony (required by law). Some also have a church ceremony afterwards, never before. If you have a church ceremony, you will need to present your civil marriage certificate before the priest will perform the ceremony. There is also the PACS, Pacte civil de solidarité, which is sort of like a civil union. It was originally intended for homosexual couples, but some heterosexual couples take this route. It offers some of the same benefits of marriage and is more easily broken.
For more information, check out the American Embassy website, Marriage Requirements in France. http://www.amb-usa.fr/consul/acs/guide/default.htm
Here is a brief summary. First, you will need from the US Embassy a notarized paper stating that you are free to marry in France, either that you were married and were widowed/divorced, or that you have never been married. You will also need a Certificat de Coutume, which basically explains US marriage laws, and that the US citizen is free to marry in France and that the marriage will be recognized in the US. For these statements, you basically show your passport, fill out some forms, and swear on your honor you are telling the truth.

Next, you need your birth certificate. It must be issued within three months of the scheduled wedding, translated into French (officially, you can't do it yourself even though anyone with French 101 could do it). The Embassy/Consulate Section will not do this, but will give you a list of official translators.
Next is the medical exam and blood test. This must be completed as close to 2 months before the wedding as possible. This must be completed before the banns will be published. If you are coming from the US, you can have it done in the US by a doctor recognized by the French Embassy. The certificate must be in French or with an official translation and is only valid for two months. The entire file must be turned in 2 months before the date.
You also need to fill out a list of witness, one or two witnesses per spouse.
*If at least one of your witnesses does not show up on the day of the wedding, you CANNOT get married. So choose carefully, maybe someone that is already in country.
Proof of Domicile- You will need at least two proofs of where you are living to present to the City Hall. Usually French couples get married in the area where the woman is from. You must get married in the area where one of you lives. You cannot both live in Paris and decide to get married in Nice for example. The banns will be published at the city hall where you are living, or both city halls if you live in different cities, or even different arrondisements of the same city.
One of the two partners must reside in France for 40 days prior to the wedding. The banns will be published ten days before the wedding to see if there are any objections, then returned to the city hall where the marriage is taking place. The ceremony is performed by the mayor or their representative, wearing the tricolor sash in a big room in the city hall. It seems to be a rather quick ceremony, with no readings or anything like that. The witnesses sign the papers, Abracadabra you are married.