« Avoir mangé du lion ».

Literal translation:
To have eaten lion’s meat.

Meaning:
To have a tiger in one’s tank.
To have incredible energy.

– Est-ce que tu as vu Michel ce matin ? Il vient de revenir au travail.
– Oui, il a dû manger du lion pendant ses vacances Son énergie est incroyable !

– Have you seen Michael this morning? He just came back to work.
– Yes, he must have eaten lion’s meat during his vacation. His energy is unbelievable!