U.S. State Department spokeswoman Jen Psaki said Lavrov and Kerry would meet on Sunday in the French capital. They spoke by phone on Saturday, following up on the Putin-Obama call on Friday.
The White House said Obama had told Putin that Russia must pull back its troops and not move deeper into the ex-Soviet republic. The Kremlin said Putin had suggested "examining possible steps the global community can take to help stabilize the situation.
Ukraine remains deeply divided over protests that led to Yanukovich's ousting and many eastern Russian-speaking regions are skeptical about the policies of the new pro-Western government in Kiev.
Yanukovich called on Friday for each of the country's regions to hold a referendum on their status within Ukraine, instead of the presidential election planned for May 25.
That election is shaping up as a context between former prime minister Yulia Tymoshenko and billionaire confectionary oligarch Petro Poroshenko, after boxer-turned-politician Vitaly Klitschko withdrew on Saturday.
Lavrov called for "deep constitutional reform" in Ukraine, a sprawling country of 46 million people divided between those who see their future in closer ties with Europe and mainly Russian speakers in the east who look to former Soviet master Russia.
"Frankly speaking, we don't see any other way for the steady development of the Ukrainian state apart from as a federation," Lavrov said.
Each region, he said, would have jurisdiction over its economy, finances, culture, language, education and "external economic and cultural connections with neighboring countries or regions".
"Given the proportion of native Russians (in Ukraine) we propose this and we are sure there is no other way," Lavrov said, and Russia had briefed Western powers and others on the proposal.
There was also a bid for regional devolution within Crimea. Its Tatar community, an indigenous minority who were persecuted under Soviet rule and largely boycotted last month's referendum on joining Russia, want autonomy on the Black Sea peninsula, the Tatar leader said on Saturday.
- By Reuters