Those games are pretty obvious, and they've often been used. We judge by the spirit of the law more often than in US. I know a company of 5-8000 people who's firing 9 managers per month [1] so they don't fall into the "group layout" category. They have to persuade them with a resignation package. They plan a "plan social" in a few months. Here's documentation about it: [3]

It's a job. See this agency, at random: [2]. My godfather was a HR manager specialized in "plans sociaux" (=closing factories when famous tech brands moved to Asia), and his job was pretty much explaining CEO of other continents that they have to put money on the table to be allowed to dump a whole factory, which they couldn't really get, obviously. The mother company has to help refurbish the local economy so workers find new jobs, or hire a job agency to find jobs and prove workers aren't just ditched. When the job is done, he writes the last two resignations: his, and the local director. The length of the process is around 2 years for 500 people. Needless to say, mafia jobs are probably safer.

[1] See "New procedures for implementing mass lay-offs" in http://www.proskauer.com/publications/client-alert/new-labor...

[2] http://www.triplet.com/50-10_employment/50-12_laysoff.asp

[3] http://uk.practicallaw.com/0-503-0054#a362756

I always knew France had insane labor laws, but they idea of having to ask permission to close a factory is being insane to me.

Also while I doubt I will ever have to, I wouldn't start a business in France under those rules.