The Greeks first tried to settle in Celtic Gaul and managed to establish a small colony in Marseille in 600 BC. Then it was the turn of the Romans, lead by Julius Caesar, who entirely invaded Gaul during the Gallic Wars (58-51 BC). The Romans brought unity and peace for two centuries of Pax Romana during which agriculture, cattle-breeding and urban development were greatly improved. 
French History 101
Middle Ages
Charles Martel, the first leader of the Carolingian dynasty, initiated the expansion of the Franks’ kingdom and stopped the Muslim advance from Spain in 732. Charlemagne (742-814) continued this expansion and conquered most of Germany and Italy to reunite most of the former Roman Empire. Shortly after his death, however, his kingdom was divided under the pressure of invaders such as the Normans (Vikings) and the Magyars (Hungarians). 
Renaissance
In the early 16th century, after a series of Italian wars, Francois I strengthened the French Crown and welcomed to France many Italian artists and designers such as Leonardo da Vinci. Their influence assured the success of the Renaissance style characterized by enlarged doors and windows, the great sophistications of the interiors. 
Grand Siècle
The 17th century was marked by a period of exeptional power and glamour for the French Monarchy. Starting with King Louis XIII and the Cardinal Richelieu who together transformed the feudal French Monarchy to an Absolute Monarchy, by controlling the opposition of the “Grands” (the Lords) and the growing power of the Protestant (siege of La Rochelle, 1628). Mazarin, Louis XIV’s regent, ended the popular revolts of La Fronde.
Revolution Era
The 18th century’s Enlightment brought thinkers such as Voltaire and Rousseau to struggle against the principles of the old regime and absolutism. In 1789, the state’s financial crisis brought social turmoil, triggering the Revolution. On July 14th, a Parisian mob revolted and stormed the Bastille prison, symbol of the old regime.
Napoleonic Era
The Revolution ends in 1799 when Napoleon Bonaparte entered Paris and was crowned First Consul at the age of thirty. A brilliant politician and a military genius, he took the title of emperor Napoleon I in 1804.
19th Century
In 1870, the Franco-Prussian war erupted, Paris fell to the Germans and France lost the Alsace and Lorraine regions. Following the defeat, Napoleon III was exiled and France’s Third Republic marked the definite end of centuries of monarchy. 
20th Century
The First World War erupted in 1914 in northeast France and after two years of German victories, fell into the horrors of trench warfare. The United States entered the war in 1917 and helped France to victory. The Allies demanded generous restitutions and payments from the Germans, who resented the humiliation for years, and was one of the factors which sparked WWII. 