"Il n'est pas à la hauteur de ce travail."
I think the French idiom is just "(être) à la hauteur", which means ≈ being able to do something (this is what my dictionary says too). Example: Il est à la hauteur de la difficulté.
But in English there is an idiom "up to the job" which also means being capable of something, and this creates confusion. English example: Barcelona weren't up to the job against Bayern (this is about football).