Battle of Lutetia
51 BCE.
Shown on the map at 48.850°, 2.350°.
The Battle of Lutetia was fought on the plain of Grenelle in what is now Paris between Roman forces under Titus Labienus and an anti-Roman Gallic coalition in 52 BC during the Gallic Wars. It was a Roman victory. Caesar offers an account of the battle in his Gallic Wars, for which he draws both on Labienus' report and an episode in Polybius's history.
Text from the Wikipedia article Battle of Lutetia, licensed CC BY-SA 4.0.