Using Metro Tickets in Paris, France
Case 5: Your Metro Ticket Doesn't Work
You enter your metro ticket, the machine light flashes red instead of green, and the gate doesn't open.
There are two reasons the machine will reject your ticket.
1. Previously Used Ticket - Check that you didn't enter a previously used ticket. If the ticket has been used before you'll see a small date stamp on the back of the ticket.
2. Defective Ticket - If the ticket is new, chalk it up to getting a dud ticket. Dispose of the "bad" ticket, and enter a new ticket into the machine.
If you're spending a week or more in Paris, avoid individual ticket hassles in the future by purchasing a Navigo pass.
Author: Cheryl Montgomery