"STUDENTS OUT OF BED DOWN THE CHARMS CORRIDOR!" -- Peeves"
The Charms corridor, which contain the Professor Flitwick’s Charms Classroom, is located on the third floor of Hogwarts. The forbidden corridor housing Fluffy in PS is nearby.
"Ducking under Peeves they ran for their lives, right to the end of the corridor, where they slammed into a door - and it was locked" (PS9).
"He followed Cedric at a distance, and saw that he was heading towards the Charms corridors" (GF20).