Mass shootings can happen anywhere that people have access to guns. Duh. Mass stabbings can happen when people have access to knives and motor vehicles can be used to run people over where people have access to motor vehicles.
Has anyone actually claimed that mass shootings cannot happen in France or Germany? Or is this another bad strawman argument?
Some countries have tried, with significant success, sensible restrictions on who can own guns, what type of guns people can own, where guns can be carried and how they can be used. The claim is not that all gun violence can be eliminated this way. Just as requiring people to obtain drivers' licenses and putting a speed limit on a fucking road is not the same thing as making the claim that speed limits and drivers' licences mean that there will be no road deaths ever.