In France it would be considered "Faute grave", a violation of the duty of discretion/loyalty to the organization. You have to give that person a few days of no

In France it would be considered "Faute grave", a violation of the duty of discretion/loyalty to the organization. You have to give that person a few days of notice but otherwise they can be terminated at will. Of course, that's the theory. Europe's courts are more politicized than in the US and laws are frequently vague. Someone might try to challenge such a firing. But the law does allow it. That's in France which has unusually vicious employment laws. In other parts of Europe it's more casual. In the UK you can be fired for more or less any reason outside of a few restricted reasons if you're within the first two years of employment. After that the rules get a bit stricter, but not enough to mean a company has to tolerate an employee bringing the organization into disrepute (which this behavior absolutely does).