As a home theater system do you recommend?

what brands are available to you?

(1) can you please define what constitutes your HT "system" ?
For example, is it ALL of the electronics, the Bluray player, the speakers, and the cables? Or do already have some 2-channel audio gear that you want to expand into a multi-channel HT rig?

(2) Given your suggested budget strata, are you content with a basic TV sound bar and subwoofer HT kit , or are you actually targeting a 2.1 vs. a full 5.1 vs a full 7.1 (or better) HT multi-channel setup?

without prejudice to any of the foregoing, your modest budget cap of €400-€500 will invariably indeed trigger key compromises, including inter alia:
(a) eliminate anything above a sound bar / sub TV-top kit or a 2.1 "HT-in-a-box" kit from a big box store for new complete systems;
(b) predicate a pre-owned selection arena rather than any new equipment purchase options if it's ad hoc components you are considering;
(c) other significant compromises beyond further detailed comment until the key questions above are answered.