That's not true at all, the troops evacuated from Dunkirk (and they fought mostly in Belgium not France) were being rearmed and in the process of being sent back to fight when France surrendered - also trapping tens of thousands of Polish soldiers who have made their way from occupied Poland to France, only to be either being captured there or spend the war in the internment in Switzerland.

Also it was a German offensive, and the Allied counterattack was a failure.

That's not true at all, the troops evacuated from Dunkirk (and they fought mostly in Belgium not France) were being rearmed and in the process of being sent back to fight when France surrendered - also trapping tens of thousands of Polish soldiers who have made their way from occupied Poland to France, only to be either being captured there or spend the war in the internment in Switzerland.