Sarkozy said such a summit, possibly under the auspices of the Organisation for Security and Cooperation in Europe (OSCE) security body, would not be conclusive but could lay the foundations for a future European security pact.
"Between now and then, don't talk about deployment of a missile shield, which does nothing to bring security and complicates things," he said referring to US plans to deploy an anti-missile system in Poland and the Czech Republic.
Call for restraint
Medvedev said his remarks on deploying missiles in Russia's western outpost of Kaliningrad were a reaction to the US plans, which Moscow sees as a threat despite Washington's assurances that they are aimed at protecting America and its European allies from "rogue" states such as Iran.
"We urge all to refrain from unilateral steps which influence security until the new pact is signed," Medvedev told the joint news conference with Sarkozy.
"Russia has never made such steps unilaterally."
Friday's French-Russian summit in the city of Nice came after EU states agreed on Monday to restart talks on a broad partnership pact frozen after Russia's August military incursion into Western ally Georgia.
The two sides still have to set a date for this.
Sarkozy said Russia had to a large extent complied with a French-brokered ceasefire in Georgia, but still needed to withdraw its troops from two disputed enclaves.
Acknowledging reservations among some EU states about restarting talks with Russia, Sarkozy said it was in the mutual interest of Russia and Europe to talk to each other.
"We do not need extra conflicts... more division, more wars, we need unity," he said.
After the summit Sarkozy and Medvedev are to fly directly to Washington to join the G20 meeting of top economies on the global financial crisis.