Automated toilets require you to insert 30 cents into a slot and a door will open, you then enter and use the facilities until you are ready to leave, then open the door with a button on the wall. If there is someone using the toilets when you arrive at them, do not under any circumstances go in if the departing user holds the door open for you. Let it close and wait till the light goes red and then insert your 30 cents for use.
Let me tell you what happens when you sneak in without paying.... A note outside informs you that the toilet is flushed between every use. This means that at first the door closes behind you and you watch as the toilet seat retracts into the wall, then sprays around the entire wall spray the lower walls and floors for about 30 seconds and then you are left totally in the dark as the lights go out.
When you finally emerge you are wet from the knees down and very embarrassed. Even know my girlfriend is still laughing.
Should you feel a sudden pain in the chest area you will be very glad to know that at various locations around Caen are placed Defribulators in which case passing doctors will be able to have the equipment at hand to re-start your heart.
I guess if you didn't watch your step and a local didn't follow the sign, you could be in for a "oh ***" momemt