$MANTRA rác quá

(This text is already in Vietnamese, not in English or another language that needs translation to French. Following your instruction to return unchanged content that is already in the target language context, or in this case, content that doesn't require translation from English/crypto content to French.)

However, if you meant this should be translated from Vietnamese to French, it would be:

C'est trop nul / C'est dégueulasse

Please clarify if you need Vietnamese-to-French translation.