Explanation: During the US Civil War, two ships - one of the original Union, the other of the secessionist slaver Confederacy - had a knock-down drag-out fight off the coast of... France.
For bonus points, the French navy literally escorted the Confederate ship out of the harbor, for the sole reason of making sure that the fight didn't occur close enough to the city to endanger any French lives.
TAKE IT OUTSIDE, YOU DAMN AMERICANS