In a joint statement on Tuesday issued after the 45-minute talks in Paris, the two leaders expressed "great concern" about the movements of weapons and armed groups in and out of refugee camps, which "negatively influence the sovereignty and independence of Lebanon".
The meeting was the first between Abbas and Siniora, officials said.
Abbas, responding to reporters' questions after the meeting at a Paris hotel, said Palestinian refugees were "guests" in Lebanon and were not above the country's laws.
Standing alongside Abbas, Siniora said they had discussed weapons received by Palestinian factions in Lebanon through Syria.
"Abu Mazen (Abbas) expressed his condemnation for such infiltration - either the weapons or the individuals," Siniora said.
Last year, a UN resolution called for disarming all militias in Lebanon, including Palestinian groups and Hizb Allah. Some Palestinians, however, have strong feelings against surrendering any arms amidst Lebanon's rapidly changing political climate.
Abbas (L) met Chirac on Monday
"We expressed our views that the presence of armed personnel and armaments outside the camps is not necessary and not helpful," Siniora said.
"As for the presence of armed personnel within the camps, this is going to be looked at in order to organise it.
"Abbas expressed support for Lebanon's efforts in the last few weeks to ban weapons outside the camps, and crack down on smuggling of weapons into the country," the joint statement said.
Terje Roed-Larsen, the UN special envoy on Syria-Lebanon, separately met Siniora and Abbas to discuss Palestinian armed groups in Lebanon and other issues related to the implementation of the September 2004 UN resolution, diplomatic officials said.
Abbas, who met President Jacques Chirac and the head of France's parliament on Monday, received a commitment from the French National Assembly to send a delegation of lawmakers to serve as observers for Palestinian legislative elections in January. After his talks, Abbas was to leave for Madrid, Spain, then head to Washington.
Siniora, on a two-day visit, on Tuesday met French Prime Minister Dominique de Villepin. After their meeting, Siniora said security in his country was "excellent" despite a recent series of assassinations.
"We hope that those who have been committing these terrorist attacks are going to stop," he said, "and we are making every effort in terms of organising our security forces and intelligence."
"Abu Mazen (Abbas) expressed his condemnation for such infiltration - either the weapons or the individuals"
Lebanese Prime Minister
"I am positive and determined that we will be up to the challenge," Siniora added.
Lebanon has more than 350,000 Palestinians, who are refugees and their descendants from the 1948 war that created Israel. They are crammed into 12 impoverished and often violent camps in Beirut and across Lebanon.
The Lebanese army has no control over the camps and does not go in, fearing bloodshed. Syria's pullout from Lebanon has prompted armed Palestinian factions to negotiate with Lebanon over giving up some weapons - a key UN and American demand that would have been unthinkable before the Syrian withdrawal in late April.