France and England were highly competitive rivals going all the way back to the Hundred Years War, but that has clearly changed at some point, and I was curious as to when along the line of history the French and British started getting along better.
A big initial point in the end of the rivalries was the defeat of the Napoleon for good. With him removed general feelings towards the French and their expansion was more friendly however not perfect.
In the 1830's a French Orléanist Louis- Phillipe took control of France and once again many of the countries formally part of the coalition feared the French may turn aggressive. However the French then allied with the UK. He did due to the government's of the two countries. Both had monarchs who were the head of state with a not so democratic parliament. The French also followed the British line when it came to the Revolution of Belgium in 1836. They preferred to have an independent country. This went a long way to calming British attitudes towards the French.