The people that were fighting were mostly peasants because people of the middle and upper classes were more included in the commerce, which was rising, and they had no reason to complain.

During the French period, the Belgians had very little to say. They were invaded, annexed and liberated by various armies. No Belgian political figures had real impacts except the Bishop of Liège.
They were a lot of wars during this period (including the Napoleonic Wars and the Italian Campaign) but they did not really concern Belgium, apart from the fact that the Belgians had to fight for Napoleon.
The French period ended when Napoleon was finally defeated at the Battle of Waterloo in 1815 by the British and the Prussians. The Allies then decided to take Belgium away from France and give it to the Kingdom of the Netherlands.

Finally, we can say that the French period influenced the future State of Belgium. As an example, Belgian law is based on the Napoleonic Code.