In France it's called a "faute grave" or "faute lourde" and according to the government's website the following reasons would be acceptable, although some are more straightforward to justify than others in case of litigation:

Faute grave:

* Being drunk during work hours

* Not coming to work without a reason

* Insubordination (refusing to do work included in your contract)

* Harassment, violence, insults

* Theft on company grounds

Faute lourde:

* Keeping non-striking employees from entering company grounds

* Intentional destruction of company equipment

* Physical violence and death threats against your employer

* Kidnapping colleagues (lol)

* Stealing your employer's clients

* Divulging secret or confidential IP

Like all legal frameworks there is some room for interpretation, I'm not an expert on the matter, it's only a translation of the government website.

I've worked in a few places where occasionally a few bottles of red would be consumed during team lunch so not all companies have the same interpretation of what a fireable offense is.

Breaking the terms of the contract.

Abusive behaviour.

Negotiated agreement with the employee.

Gross misconduct (evaluated in laws, usually things like directly acting against the company on purpose, like poaching contracts etc.)

Employee literally breaching the law (one example from Polish law would be turning up drunk or high at work)

Misconduct. E.g. not fulfilling your contractual duties as an employee or actively causing damage to the company. Still, a warning needs to be issued before a termination in all but the most severe cases.

(Germany)

Breach of contract or gross misconduct are usually serious enough. But it has to be a reason you'd be happy defending to a court, not just the American "I don't like this guy".