Kouchner met civil representatives before meeting Berri, a member of the Shia-led opposition, and then lunching with Fouad Siniora, the Lebanese prime minister.
He was expected to meet other political leaders, including members of Hezbollah, later in the day.
The resignation last November of six pro-Syrian ministers, five of them Shia, sparked the current political standoff, the country's worst since the end of the 1975-1990 civil war.
Hezbollah, the Shia group backed by Syria and Iran, is pushing for the opposition to be better represented in government in order to give it veto power.
But the majority insists this can happen only if Hezbollah agrees to stop blocking parliamentary sessions. A certain number of parliamentarians are needed for presidential elections to be held. Emile Lahoud, the president, should be replaced by a November 25 deadline.
If the parties fail to resolve their differences in the coming weeks that could spark a power vacuum. Even worse, the creation of two rival governments could plunge the country into chaos.
France has taken the lead in trying to resolve the crisis, gathering all the parties for a conference near Paris earlier this month and sending a top envoy to the region for consultations with all the key players.
Kouchner on his arrival in Beirut late on Friday said a solution to the crisis lies "in the hands of the Lebanese."
"There is little time left for this dialogue to take place," he said. "My trip here is but a step forward and there will be others."
Kouchner is due in Egypt on Sunday to meet the foreign ministers of Egypt and Saudi Arabia and the Arab League secretary general to brief them on his Beirut visit.