Just because it's there in the contract doesn't mean it's legal.

I'm not sure which European country you are referring to, but as a German I'd look at you funny if you had the audacity to put something like that in an employment contract (but honestly, I very strongly doubt any employer would do so in the first place).

In the UK I've signed a few employment contracts with such clauses, that If I produce something outside of working hours the company still owns it.

I signed the contracts anyway assuming that most likely the company would not be interested in what I created outside working hours (or even know of it) and that they would only get interested if it becamse really successful, in which case I would probably have the means to defend it.

> Just because it's there in the contract doesn't mean it's legal.

No, but should be likely that it is, right? Not worth the risk to put such clauses in there otherwise. And I was talking about the UK.