A sensor (1) having a housing (2) defining an internal volume (3), a movable part (4), a detector (5) for detecting movement of the movable part (4), a transfer mechanism (6) passing through a first opening (7) of the housing (2) to control movement of the movable part (4) from a first external zone (8), and a first sealing structure (9) for opposing the passage of fluid coming from the first external zone (8) towards said internal volume (3). The housing (2) includes a second opening (10) extending between the internal volume (3) and a second external zone (11); and a second sealing structure (12) between the internal volume (3) and the second external zone (11), the second sealing structure being adapted to break so as to allow fluid to pass as soon as a first predetermined pressure difference is exceeded.