Frederic Antonetti's team finished sixth last season and lie fifth this term, a point above improving Marseille and eight off leaders Paris Saint-Germain.
The new-found wealth of PSG may mean the title is out of reach for Rennes but the flood of signings at the capital club has meant benefits for other Ligue 1 outfits.
"This is a club which is growing in power. I hope we can do even better than last season," Erding told reporters at his unveiling.
"The coach really wanted me and I think we share the same philosophy. He wanted a striker with my characteristics."
Rennes' general manager is expecting big things.
"We will see if he is a great coup. I hope so," he said.
"I hope to already be in the squad," the French-Turkish player added.
Antonetti's mind could be swayed by the fact last term's runners-up Marseille are weakend by the likes of Andre and Jordan Ayew being away at the Africa Cup of Nations.
