According to Article 222-13 of the French Penal Code, “an assault on a public official, including the President of the Republic, constitutes a criminal offense and is punishable by up to three years in prison and a fine of €45,000.”
France’s First Lady at the Center of Controversy: What Does the Law Say About a Presidential Slap?

And it is precisely such a “slap” that the entire internet is now talking about.
A viral video captured at Hanoi Airport during the arrival of French President Emmanuel Macron in Vietnam appears to show two hands — seemingly those of First Lady Brigitte Macron — striking her husband’s face just moments before he stepped off the presidential plane.
The footage spread rapidly online, sparking heated debate between those who saw it as a playful marital moment and others who interpreted it as a tense dispute caught on international cameras.
President Macron responded with a smile and an official wave, while Brigitte avoided his hand and leaned against the railing, further fueling speculation.