Social media users are talking online about a large-scale plan to defecate in the river after France's President Emmanuel Macron and Paris Mayor Anne Hidalgo claimed it was safe enough to swim in.

Here's the deal ... a couple months ago water charity Surfrider Foundation Europe claimed it had tested the water in the Seine multiple times over the course of six months from September 2023 to March 2024 and claims they found a shocking amount of bacteria in the water.

In response, Macron, Hidalgo and other officials said they'd in the water and go for a swim to prove how safe it is ... and, many started joking they should turn the river into a latrine to prove their point.

Welp ... it seems the joke's gotten a bit out of hand -- 'cause now there's a website including a calculator to help people figure out what time to leave their droppings in the river so it will flow into Paris at noon tomorrow if they live in the countryside.

Plus, influencers are talking about the protest like it's really going to go down ... and, they're including snaps of the Seine which we gotta say does look pretty dang green.

Of course, this comes just weeks before the Paris Olympics ... which has open water swim events scheduled to go through the river. BTW, many in the city are pissed the Olympics are happening at all -- so, this may end up being a catch-all protest for pissed-off Parisians.