Last weekend I went to a wonderful French wedding in the south of France. I've known the bride since she was a toddler and am friends with her whole family, so it was special to me.
French weddings, at least the ones I've been to, which tend to be traditional because my French friends are mostly from the 16th and 7th arrondissements of Paris, are a bit different from American ones. In fact, the church wedding is not the legal wedding, as it can be in the U.S.; only the wedding at the mairie is the official one. This often takes place on a Friday, so if you're curious to see one, hang out outside any mairie in Paris on a nice Friday morning or afternoon. You'll see a crowd of well-dressed people, the women in hats, bright colors and high heels, milling around the bride and groom before and after the short ceremony. (Nowadays, this ceremony can be for a bride and bride or a groom and groom instead.) For those who don't want a religious ceremony, this is the main wedding. The mairie has a dedicated room for the ceremony and does its best to make it a pleasant occasion.
Salle de mariage in the mairie or town hall of the 16th arrondissement, Paris
Families I know, though, even the majority who, like other French people, don't set foot in a church from one year's end to the next, usually have a religious wedding, too. In France this is almost always in a Catholic church, by a priest who ideally is a relative or friend of the family. In this case, the priest was so keen on officiating that he put off going into the hospital for an operation. He wasn't very well during the ceremony, but he was beaming all the same.
A custom I really like in Europe is that instead of bridesmaids, who are the bride's own age and often look uncomfortable and self-conscious in dresses they hate*, European brides are preceded by a bunch of little children, very excited and dressed in cute outfits. Their misbehavior is part of the fun!
*My sister got invited to a party where all the women were requested to wear a bridesmaid's outfit that was hanging uselessly in their closet. It was pretty funny.