Cédric Vaivre - who owns a boulangerie in the commune of Lusigny-sur-Barse, which is popular with summer tourists - was fined after officials discovered his shop had been open every day during the tourist season.
Mr Vaivre said that he needed to stay open during the summer, in order to keep up with demand and to help turn a profit to shore up the quieter winter months.
But boulangeries are not allowed to open seven days a week due to two decrees (one from 1994 and another from 2000), if no exemption has been granted.
Mr Vaivre was granted such an exemption in 2016, but this was not renewed in 2017, prompting the fine.
Now, the boulanger is fighting the decision, with support from the village mayor.
Mayor Christian Branle says that despite the decree, local shops should be able to adapt to local needs.
He said: "We must have a bit of common sense. We're in a small, rural commune, in an area where there is not a huge amount of business [except in summer]. As long as people want the service, let's allow people to work."
Local residents have also come to Mr Vaivre's defence and a support petition has gathered 2,500 signatures so far.
Anne Roger, creator of the petition, spoke to new channel LCI and said: "It's unthinkable that you would be punished for opening your shop. It's important to defend our local, rural businesses so that they continue to survive."
Another resident added: "There is nothing worse than closed shops when there are tourists", and defended Mr Vaivre's right to open every day.
Mr Vaivre remains hopeful that the fine will be waived, and is hoping to meet the official who imposed it, to explain his case.
I always thought it was a prerequisite to work for the (any) government.