Quite literally jailhouse rock, viewed through the double-door entrance of Honfleur's former prison, which dates to 1734. Le Vieux Honfleur, a charming and much visited port village, converted the prison into an ethnography and popular arts museum in 1896.
It's not legible in the photo, but a small note attached to the iron gate asks people not to shake it.
une prison: a prison
la geôle: the gaol; the jail
un geôlier: a jail-keeper
le rock du bagne: jailhouse rock