You fire them… it’s harder than in other places put you can still do it. You just need a valid reason! I had at least a couple of colleagues other the years being fired! At least employees are not victims of the employer every whim! And this is a good thing!
Country law state 30 days for my kind of contract… but since I work more than your normal contract (in France the work week is 35h a week whilst I work 37h) I get extra 5 days. On top of that I have 5 days for sick children and unlimited sick days.