The other 40 defendants faces charges including corruption, tax evasion and embezzlement.
Despite a promise to explain his role, Gaydamak fled France and is currently living in Israel.
He even stood for Mayor of Jerusalem while attempts to extradite him from his adoptive home failed in the courts.
Falcone, who holds French, Canadian and Angolan citizenship, was named Angola's ambassador to Unesco, the United Nations cultural organisation, in 2003 and has claimed diplomatic immunity in the case.
But David Chater, Al Jazeera's correspondent at the court in Paris, said the judge has ruled that Falcone will not receive immunity as he hands down the verdict.
"This is one of the murkiest affairs that has been exposed in court," our correspondent said.
"Many people I've been talking to here ... say that really they've only half-lifted the veil that many people have escaped justice and they've escaped the spotlight."
|Gaydamak currently resides in Israel following failed attempts at extradition [EPA]
The alleged weapons arsenal, which included 420 tanks, 150,000 shells, 170,000 anti-personnel mines, 12 helicopters, and six warships, is said to have propped Eduardo Dos Santos, the Angolan president's government during its war against the US-backed Unita rebels.
The arms sales began in 1993, when Francois Mitterrand was French president and continued into 1998, three years into the presidency of his successor, Jacques Chirac.
Jean-Christophe, Mitterrand's son and former Africa advisor, faces a year in jail on charges of receiving $2.7m from Falcone, as well as millions in "consultant fees" for overseeing the arms deals between 1993 and 1998.
Others facing suspended jail sentences include former interior minister Charles Pasqua, who says it is a political motivated plot against him, and novelist Paul-Loup Sulitzer.
Bribes and kickbacks
|Angola is littered with landmines, a legacy of the civil war that killed thousands [EPA]
Prosecutors have also argued that the shipment was in itself illegal, although the main defendants dispute this, and claim that millions of dollars were skimmed off the contract to pay bribes to senior French and Angolan figures.
Although no Angolan officials have been indicted, court papers allege that Dos Santos and his inner circle received millions of dollars in kickbacks.
Several defendants have also said the trade was carried out in full view of French authorities but that the government kept quiet to protect an important source of oil.
Angola pushed to have the trial abandoned, as relations soured between the countries.
In 2008, Nicolas Sarkozy, the president, visited Angola in an effort to mend ties strained by the case.