The Treaty of Neuilly-sur-Seine was a peace agreement signed on 27 November 1919 that required Bulgaria to cede various territories. It was arranged after Bulgaria’s defeat in WWI.
The agreement saw Bulgaria lose land to Greece, Romania and Yugoslavia, as well as its access to the Mediterranean. Like the other defeated countries, it was forced to disarm.
The nation was also forced to reduce its army to 20,000 men, and to pay reparations of £100 million under the agreement. The Treaty was signed in Neuilly-sur-Seine in France – as you might have guessed from its name.