Robitaille’s cameo occurs in , titled "The Secret of Success" (which originally aired as part of a hour-long special, Phineas and Ferb’s Quantum Boogaloo , but the episode stands alone).
If you're interested in learning more about Luc Robitaille, here's some information about the character: luc robitaille phineas and ferb
If you're interested in learning more about the characters in Phineas and Ferb, here are some main characters: Robitaille’s cameo occurs in , titled "The Secret