French brides often carry orange blossoms in their bouquets. They originally connoted virginity, but now connote "first marriage". It's important in French weddings to have very fragrant flowers if at all possible - the fragrance was originally meant to ward off evil spirits.
French wedding receptions are not decorated like Anglo receptions are. They are loaded with masses of fragrant flowers - flowers on the tables, at the head table, surrounding the cake, everywhere - but other than a few bows and lots of little cloth bags of dragées (little sweets like Jordan almonds or sugar-coated chocolates) entwined into the bows and flower arrangements, there will be no other decorations. Candles are rarely seen these days, if only because the fire code often prohibits them.
At the reception, the first drink the bride and groom take is from a two-handed cup called a "coupe de marriage". The couple also drink all toasts from it (hence its English name, "toasting cup"). Google it to see how it's used.
As for food, you have the entire vast catalogue of French food to choose from - lucky you! Everything in France eventually makes its way to Paris, so a dish from any part of the country would be fine. The only thing to remember is that if you have wine at your French-themed meal, make sure it's really French. Some American vintners are sneaky Petes, sticking French flags on wine from grapes grown in Oxnard, California and the like. Usually it's the bad stuff too.
French wedding meals often begin with an aperitif for adults - something like a fortified wine, to stimulate the digestion. You can skip this. The second course is passed hors d'oeuvres (one plate per table, for instance) followed by a plated appetizer - a common French wedding appetizer is a small tomato tart called a Tarte Tatin, but I've also seen fish and, rarely, seafood appetizers. (I live 1,000 miles inland so they're not common here.) Beware that in French, the appetizer is called the entrée - we English misuse the word.
The appetizer is followed by the main course. Depending on where you live (April is still winter here but could be early summer where you are), you could go with hearty French country fare such as boeuf bourguignon or coq au vin or with more elegant urban dishes such as roast tenderloin of beef, duck a l'orange, or turkey breasts in a raspberry sauce. The more sophisticated the dish, the more important it is to have an artist in the kitchen: stews and braises like coq au vin don't look as refined on the plate as a beautifully presented slice of roast garnished with fresh herbs.
After the main course there is always a cheese course, and then a dessert course. The wedding cake is not part of the dessert course.
At the end of the meal each adult is given a small cup of espresso and, if he or she wants, a drink of fortified wine, brandy, or a similar after-dinner drink. Hard liquor (with the exception of brandy) is not as commonly drunk at French weddings as it is in America. A child may get a small glass of milk with a little decaf espresso and sugar in it.
The traditional French wedding cake is a croquembouche. It's made of cream-filled puff pastries called profiteroles assembled into a shape. The traditional shape is a pyramid, but I've also seen them in the shape of a Greek column, a windmill, and in one amazing case a ten foot tall Michelangelo's David. (The last was considered very nouveau riche, but it was gorgeous.) The pastries are stuck together with caramel and the entire thing is coated in caramel. Google it and you'll see.
The final real French touch is to have onion soup with croutons served to the wedding party and any close family remaining after the bride and groom and the bulk of the guests leave. This is done because the French reception is often longer than an American reception, and after three or four hours the wedding party (who have been up since 6 AM getting ready and who probably skipped a meal or two earlier) are probably hungry again. Remember, too, that French meal portions are smaller than American meal portions.