Ok in Denmark the system is that you get hired, if they fire you in the first month you get 2 weeks severance, after which you have (IIRC) 3 months, this part is somewhat based on seniority / contract some times you might get a 4 month severance period.
You can be fired for basically any reasonable reason though.
I again have a hard time believing you need to set fire to the office before they fire you, don't French companies ever downsize?
It's an hyperbole. Downsizing is allowed, but there's some heavy paperwork involved, you have to meet some guarantees, etc. The company can't do it at will. (Then again, I'm not a company owner, I don't know the details)
You can be fired for basically any reasonable reason though.
I again have a hard time believing you need to set fire to the office before they fire you, don't French companies ever downsize?