French:
Rubber : caoutchouc (we say rubber and latex)
Master: Maitre
Slave: Esclave
Hood: cagoule
Mask: masque
Collar: Collier
Cuffs: menottes/bracelets (depends the style)
Blindfold: Bandeau [for the eyes]
Boots: Bottes
Harness: Harnais
Gasmask: Masque à Gaz
other words are the same (like bondage)