I think he meant the labor laws are protecting more the employee than the employer, notably on the firing part. So, as far as some theories go, if it is hard to fire employees, employers will be more reluctant to hire, reducing worker mobility.

But I only have a small experience of the consequence of our current labor laws (which are very hard to change, the current gov tried last year and got massive protests for their trouble).

Edit: Also the employment taxes (the one paid by employers) are very high in France (half of the salary +/-).