Fournier's men top Ligue 1, albeit having played a game more than second-placed Paris Saint-Germain, but were beaten 3-0 by Saint-Etienne in November's reverse fixture.
Ahead of this weekend's derby, Fournier backed Lyon's players to show how much they have developed since that meeting.
"We did a lot of bad things during the first leg. We were not committed enough, that's for sure," said the coach.
"My players were too shy in the game. It was insipid.
"There are a lot of things to change. Since then, a lot of water has flowed under the bridge.
"Some players are now more experienced. We count on them to show that our level has increased since then."
Lyon may have slipped to second in the table by the time they host fifth-placed Saint-Etienne, with PSG in action at Nice on Saturday.
