I've noticed several old threads regarding speeding tickets and travelers concerns regarding unpaid fines; so I thought it would be helpful to post a current link that will actually show your status: https://www.antai.gouv.fr/?lang=en
Be sure to always go directly to an authorized french government website. They all end with gouv.fr. In my case, I became aware of a speeding offense long after even the latest period of payment. When I went to the above website, it stated that I was no longer being prosecuted for the offense. I don't know if it "timed out" or if due to political pressure regarding radar traps, that they have changed they position on using them.
I found the above link thanks to Jean Taquet and his website : americancommunityinfrance. "Jean is a French consultant and associate member of the Delaware State Bar Association"