the term 'master' is not used in French when speaking of a bedroom. French people tend to say 'la grande chambre' (the large bedroom) or 'la chambre des parents' (parent's bedroom), or 'la chambre principale' (the main bedroom) depending of what they see fit.
There is also a preposterous fad on commercial leaflets, to speak about 'la suite parentale' (the parent's suite).
Chambre des maîtres
la chambre principale
Chambre des maîtres
a master bedroom
'the bedroom is ..' translates as "la chambre est ..." in French.
bedroom of the parents
la chambre de ma soeur
My bedroom is 'ma chambre' in French. This is a feminine noun, even when it's a boy's bedroom.
The bedroom is 'la chambre' (fem.) in French.
To say "my master" in French, you would say "mon maître."
une chambre
ma chambre
ma chambre
"C'est la chambre des parents, c'est la chambre principale." Literally, "It is the parents room, main bedroom."