I'd be really curious to know which contracting company you worked for. What you are stating is not true: when you are transferred back to the contracting company (for whatever reason), if they are still your employer, this company has to pay you. Even if you don't work for a client. This is not that uncommon actually to be in that kind of situation. However, contracting companies are well known to be really hard on their contractors (especially developers), if they saw that you would believe that you wouldn't get paid unless you work free extra hours, that doesn't surprise me that they'd use that. But it would never have happened. In France, work laws are much more in favor of the employee, they would never have gotten away with not paying you.