One Frenchman is fighting to put a smile on the rest of his "depressed" country by trying to overturn a law that prevents people from showing any kind of emotion on their photos for passports and identity cards.
The Paris Court of Appeals is tackling the matter on Thursday after a man, described as a senior civil servant, lodged a complaint after being infuriated that his ID photo got rejected for being "too smiley".
He claims that he wasn't actually smiling and actually had a neutral face - it's just that the corners of his mouth were raised.
And the lawyer who is taking on the court of appeals reckons it's about time France lightened up a bit and let people sneak through a smile. After all, there is no legal mention of banning smiles, he argued.
"Is it really responsible, in a depressed France, that the authorities forbid the French from smiling?" the lawyer said.
"If they stopped asking the French to be miserable on their IDs, they'd give the morale of the nation a little lift."
He said that, similar to the enigmatic smile of Mona Lisa, people should in theory be allowed to smile with their mouths, as long as they keep their lips together and their expression neutral.
"If we win, the French will be able to offer a friendly face from their country at all the world's borders," the lawyer said.
So what actually constitutes a smile?
The rules used by authorities are quite specific about saying that for an ID or passport photo at least, your mouth has to be closed, that much is for certain.
"The subject must have a neutral expression with their mouth closed," is how the Paris administrative closed the same case back in 2014.
But what about the corners of your mouth? Can you get away with rising them slightly?
This is exactly what the Paris court will figure out on Thursday.