Earlier quoted context omitted.
There's a short-term effect there that might be positive, but a long-term effect that would be negative. There's a reason that a lot of companies won't hire in France or other specific locales where the difficulty in getting out of an employment relationship is so high that it makes it undesirable to get into that relationship in the first place.
Yes but you do actually want access to the French market so you will likely need employees in France.
A few but not a lot. You would need a corporate entity, a sales team if you do B2B or want to get government contracts and a few employees to deal with the special snowflakes regulations and keep up with what the bureaucrats are making up. But you don't need engineers specifically in France. Even localization can be contracted out, since it's a well defined scope.
Not only that, but France is right next to Switzerland where there's a concentration of French engineering talent. That and, it's relatively straightforward for these guys to just transfer to the Bay Area.