>>But arresting foreign nationals in other countries for violating US sanctions?*
You steal a car in Belgium. Belgium investigates, charges you and issues an arrest warrant. In some cases it goes to Interpol or EU-wide systems. You go to Germany for a vacation and your name is flagged. Yes, you are arrested by Germany for violating Belgian laws and the extradition process starts.
You can challenge the arrest on a few basis (such as "Iran wants to jail me for criticizing Mullahs") but other than that, countries do help each other catch criminals. "Violating US sanctions" is apparently a crime in USA and Canada more or less has the same view on major international relations so he is likely screwed. (I think the arrest is almost automatic everywhere, but then courts and justice dept decide on whether to extradite.)
You steal a car in Belgium. Belgium investigates, charges you and issues an arrest warrant. In some cases it goes to Interpol or EU-wide systems. You go to Germany for a vacation and your name is flagged. Yes, you are arrested by Germany for violating Belgian laws and the extradition process starts.
You can challenge the arrest on a few basis (such as "Iran wants to jail me for criticizing Mullahs") but other than that, countries do help each other catch criminals. "Violating US sanctions" is apparently a crime in USA and Canada more or less has the same view on major international relations so he is likely screwed. (I think the arrest is almost automatic everywhere, but then courts and justice dept decide on whether to extradite.)