President Nicos Anastasiades and Turkish Cypriot leader Mustafa Akinci are scheduled to meet in Berlin on Monday alongside United Nations Secretary General Antonio Guterres.
A German foreign ministry spokesman said Berlin was providing financial and logistical support for the "informal, trilateral" meeting but not playing a part in the talks.
In Nicosia, one of the protest organisers, Christos Tombazos, told AFP: "We're here to press our two leaders to look for a creative way to restart negotiations."
Some 80 organisations from both sides joined Friday's march, and said they were delivering a letter to the two leaders calling the Berlin meeting "a crucial opportunity to revive the peace process".
"Cyprus is too small to be divided, but big enough to welcome us all," they wrote.
In August, the leaders held an informal meeting in the buffer zone dividing the capital Nicosia, but failed to make any breakthrough in reviving talks.
Turkey has had troops stationed in the country since 1974 when it invaded and occupied its northern third after a coup sponsored by the military junta then ruling Greece.
The Greek Cypriot Republic of Cyprus controls the southern two-thirds of the island, which joined the European Union in 2004.
Only Ankara recognises the breakaway self-declared Turkish Republic of Northern Cyprus (TRNC).
Turkey still maintains between 30,000 and 40,000 troops in the north.
In 2003, crossing points opened along the UN-patrolled "Green Line" which had until then hermetically divided the island in two.
Several rounds of UN-brokered talks on reunification have taken place down the years between Greek Cypriot and Turkish Cypriot leaders, but they have always collapsed.
Carrying signs reading "Status quo is a countdown to permanent partition", demonstrators said they were worried that the passage of time would make reunification impossible.
"It's getting more difficult every day because of the number of settlers coming from Turkey," said Hulya Akbil, a Turkish-speaking Cypriot.
The retired teacher said Turkish settlers now outnumber Turkish-speaking Cypriots in the north, and their presence is a major stumbling block to reunification.
Many marchers on Friday stressed their shared common identity as Cypriots.
"I'm a Cypriot who is Greek-speaking, but we are Cypriots first," said author and Unite Cyprus Now activist Marina Christofides.
Monday's Berlin meeting is "an opportunity not to be missed", said Kemal Baykalli, a Turkish-speaking Cypriot and activist with Unite Cyprus Now.
"Ultimately it's up to the leaders to make it happen," he said. "But we're here to say that we as Cypriots are ready."