French bicycles are in vogue now because they were the hottest ticket during the bicycle boom. The inexpensive Italian models were junky and the good stuff was too expensive. The Japanese components worked well but the frames were dead and they had no reputation. The French bicycles were lively, priced right and had the reputation via Peugeot, who did a wonderful marketing job, emphasing their racing success and playing up their association with the only cyclist familiar to Americans, Eddy Merckx, even though he hadn't rode for them in several years. Everyone wanted a Peugeot. If you couldn't get one, the next best choice was another French brand.
I suspect a lot of people are trying to re-capture their youth from the boom period. They are trying to find that bicycle they used to own or the one they wanted. In most cases, that was a French bicycle.
I owned a 1974 Jeunet Professionel, which was a delighful bicycle. However, I've moved on. The majority of the popular, vintage French bicycles emphasized functionality over fine workmanship and elaborate finishing. I can appreciate them for they were, but they no longer have special appeal to me. Last year I sold my remaining French bicycle, a St. Etienne. Of course there are some exceptions, notably Herse and Singer.