Nick Heidfeld is taking Lotus Renault GP to the High Court after the team axed him in favour of Bruno Senna.
The team confirmed earlier this week that Senna would replace Heidfeld at this weekend's Belgian GP with the nephew of the late Ayrton Senna also contesting the Italian race in two weeks' time.
However, Heidfeld is adamant he has a valid contract and is now taking the team to court over his axing.
His legal representative Dr Stefan Seitz said: "The interlocutory decision of the court does not infringe on the fact Nick has a valid contract to be one of the two main drivers of the team.
"This position is disputed by the team for apparently purely financial reasons, but we do not intend to rest before Nick's legal position has been fully restored."
Meanwhile, the German's manager Andre Theuerzeit is determined to see the 34-year-old return to a Renault race-seat from the Singapore GP onwards.
"I am disappointed the team is allowed to let another driver take Nick's seat for the next weekends," said Theuerzeit.
"However, I certainly am confident we will be able to enforce a fair solution for Nick in the further proceedings."
Heidfeld: I have a valid contract
Senna confirmed for only two races