The ticket was issued when she tried to shorten her journey by walking counter to a one-way system at Concorde.
Paris metro operator RATP said the system was needed to control flow and prevent "incidents".
The woman's partner posted a picture of the fine on social media, saying "Bravo for this racket."
His post led to a number of other metro users complaining that they had been targeted the same day.
One, Lucile, told Le Figaro she thought the signs were there simply to make sure people did not get lost in the corridors.
