Why would Iran attack French ships? I don't know. Why would Iran arrest employees of the British consulate?  People get upset about things, and disputes over power occur.  French ships, like the ships or other assets of any country, have been attacked by foreign powers for as long as their have been countries and ships. Shit happens, as they say. The question for people like the French is whether such kinds of attacks have been fewer or greater during "Pax Americana."  And is it because of American dominance of world affairs, or despite it?