"You might think they made it to please politicians"
This is not even a secret. The original office existed because of certain folks not wanting to relocate, but it was only ever grown to please politicians. It was even made into a media event with eric schmidt and the president of france.
"but I think the real reasons is for recruitment"
This is false, sorry. I wish it wasn't. As I said, i'm pretty sure this isn't even secret.
"If they want a chance to hire them they need an office in France."
I'm just going to be blunt here: They did okay without having to hire them before, they would do okay without having to hire them afterwards.
This is not a knock on french engineering folks, really, it's more a statement "there is sufficiently high quality supply of engineers elsewhere that it is not actually necessary to be there".
Heck, the engineers in france are probably even significantly more expensive than elsewhere, too.
The office was not made, or expanded, for recruitment. It was, like a lot of other companies do, to have skin in the game.