I loved that gentle yet classy slap in the face that France (most likely directed by Germany) gave to the UK when they closed the border in Calais for a while.
Macron has been taking a harder stance than Merkel for a while so it seems more likely that this is a response to the UK threatening to guard it's waters with Naval ships.
Obviously they have a right to do so but reminding your friends that you have guns isn't the most polite way to negotiate.
It was certainly an interestingly timed move in any case and a sharp reminder that "taking back control" of the borders goes both ways.