We had just returned to the United States after a road trip in the French countryside when we received an e-mail from our car rental company, SIXT, notifying us that they were charging us a $25 ticket-processing fee. We had no idea what this meant until a few days later when we received another email, this one more official looking and in French, from the République Française. (Yes, the entire country.)

The email included a link to read it in English, but it didn’t work, so after much work on Google Translate, we figured out that we had received a speeding ticket from a camera detector. We had noticed signs for speed cameras all over the countryside and had been careful to maintain our speeds, sometimes to the frustration of impatient drivers behind us.

Our research shows that speed cameras are, as elsewhere, a controversial topic in France. In fact, since the start of the gilets jaunes (yellow vest) protest movement last year, more than 75% of the nation’s cameras have been destroyed by vandals, costing the country 660 million euros (more than $700 million). We were (un)lucky enough to have been captured by one of the surviving cameras.

The ticket charged us with going 117 kilometers per hour (72 mph) in a 110 kph (68 mph) zone. We were a bit surprised that a 4 mph increase over the speed limit triggered a ticket. If that was the case, we imagine everyone on the road that day was flagged. It turns out that a 5% increase over the speed limit is enough to get penalized.

Because our excessive speed was minimal, the fine of 45 euros ($50) was the minimum amount. If we had been going 20 mph over the limit, the fine would have tripled.

There was a process to contest the ticket, but we didn’t think a trip back to France to do so was warranted — although a week’s more of crepes and Breton butter cakes was tempting. With nightmares of being arrested at French customs on our next trip for an outstanding traffic ticket, we duly paid the fee online. But with a $75 lesson learned (ticket plus the SIXT fee).

When you’re driving in a foreign country, ask the rental company about local regulations, in particular whether speed cameras are used. In many cases the areas with cameras will be clearly marked, so be even more cautious in designated speed zones. Take the speed cameras seriously. We thought we had but, obviously, not enough.

Philadelphia natives Larissa and Michael Milne have been global nomads since 2011. Follow their journey at ChangesInLongitude.com