First, France loves peace since 1940 where it was defeated (surprisingly easily) but it wasn't always the case.
In history, France is the country in Europe that made the more wars (and contrary to what many Americans think, it's also one of the most successful of all time).
France was surrounded by enemy countries : Mainly Spain, Germany, Italy and UK. It needed to have a great power and to be able to resist any war.
France attacked England first with the Norman invasion.
Later, England attacked France in order to keep its territories there and was defeated in the Hundred Years' War.
Then France was occupied fighting everybody in Western-Europe and England sided (more or less) with France's enemies, wanting to balance the power.
When France finally won against everybody in Western-Europe after the Thirty Years' War, it took control of North America. Later the UK came and defeated France. France then help the Americans fighting the UK and so attacked the UK everywhere on the seas before beating them in Yorktown.
Then Napoleon came and started to invade all Europe (except the UK > British Channel).
The UK defeated the French navy and after the failed invasion of Russia, allied with the rest of Europe to defeat the French in Waterloo.
Then the 2 countries started to colonize other countries and created the biggest colonial empires.
They finally allied and fought side by side against Germany and, with some help of the US, won WW1. (France didn't lose WW1, it was the main Allied power)
In WW2, France was defeated and had to be liberated by the UK and the US. Churchill was very anti-French, De Gaulle was very anti-English/American , and so even after the war there were some tensions between France and the UK. Even now, the UK is considered in Europe and mostly by France to be the pet of the USA and anti-European whereas France created the European Union and wants to balance the power of the USA.
For centuries, France and the UK were the two most powerful countries in the world and so became big rivals. However England/UK wasn't always the bad guy. For a long time, France had been the most dangerous nation in Europe, so it was a good candidate to inspire hatred, fear, reject... It's still the case because France never shuts up in front of the USA/UK.
I think the UK was probably the good guy until the colonization. Now, France is a peacekeeper whereas the UK always sides with the USA, which aren't very peacekeeping.
However you can say that if Germany hadn't obtain the title after its two world wars, France would be considered the most agressive nation of all times.
(Very simplified version of history)