I'll take the liberty of doing so, and if other staff want to make this an 'official' warning they may, but:
@Azertyhuuh
This is to let you know that off-topic posts are against the rules, and are considered derailment. You should avoid making them at all.
If you wish to tell a joke, that's fine, but it should at least be paired with with an on-topic post. For example, if you make a post arguing who you think should win the match, then add a short joke at the end about how your favorite character would beat them too, that's fine- but as its own standalone post it's simply too unrelated.
This isn't a serious violation if it's not excessive, but I wanted to make it clear to you that it is technically our policy.
General Discussion threads are indeed given much more leniency, but are not immune to this policy and also have set topics in most cases.