I myself am not from Europe so i dont know what is available to you or what the prices are in your area. For these types of inquires its better if you post a couple of laptops that you've found and ask for an opinion.
But to answer your question a Laptop with at least an i5 and a discrete Graphics card GT750m if that is in your price range for a pretty solid laptop.
BUT if i am understanding correctly, the only game you will be playing is league of legends, which is not a particularly intensive game so an i5 (non- ULV) with its built in HD 4600 will be able to play league maxed out (even on 1080p as the internet claims)
even an i5 ulv should be able to play fine with maxed settings at 1366 x 768.
So... any laptop with an i5 (ULV or not, preferably 4th gen.) will play league no problem at max settings (assuming that is what you are aiming for).
Also any laptop with an A10 apu would be more that sufficient for league as well.
Hope this helps!