I bet French business owners would *love* to be able to pay them under the table and get some actual work done. Heck they wouldn't have to work for such low wages like they have to in the US in order to undercut American workers.
Native French workers are too busy striking for outrageous benefits and I imagine France's current illegal immigrants (from across the Med) have figured that all they have to do is start screaming racism and burning cars and the French government caves like...well, like the French government!
I was being sarcastic, but the more I think about it, the more it sounds like a good deal for Mexicans, and for France.
They could restore France's Christianity, repopulate France will a good labor force, and offset the Muslim population explosion. Heck, they could prevent Europe from becoming Eurabia, and prosper at the same time. PLUS, they would be able to relearn their Spanish roots by visiting Spain during the ample holiday time they would have from working under France's labor laws.