Sly Cooper: Thieves in Time - Paris Prologue

#1) This mask can be found during Sly's portion of the mission. As you approach the skylight and have to pickpocket a key from a guard, you'll have noticed a structure that was lit up and colored orange. Get on top and go behind to find the mask on the ground.

#2) This mask can be found during Bentley's portion of the mission. When you get to the second open area, turn left and look for the mask in the dead end area with the grate.