This used to be the best option and you should be careful of the kind of information you find on internet about this option since things have changed pretty recently.

Now, if you would like to get married in France and your american fiance(e) is not a french resident, you will need to first get married and then file right away for a K3 visa which will allow you to go to the USA while the green card is processed instead of waiting outside the USA. Ther process is, I believe, quite similar to the green card application process.

 You can also decide to wait in France until your green card is process and simpy not apply for the K3 visa but I doubt this is any good solution to any newlywed couple.