Boualem Bensaid and Smain Ait Ali Belkacem, both aged 34, are already serving 10-year jail sentences for membership of the Algerian Armed Islamic Group (GIA).
Bensaid is also serving 30 years for a failed attack on a high-speed TGV train in August 1995.
Around 200 people were also injured in the bombings, leaving the city in a state of shock.
The worst attack happened on 25 July at the Saint-Michel suburban railway (RER) station - when all of the eight fatalities occurred.
Explosives and nails had been packed into a gas bottle, and the explosion caused horrific injuries.
Evidence
Other devices were planted at the Maison Blanche metro and Musee d'Orsay RER stations.
Bensaid had been accused of planting the Saint-Michel bomb and being part of the Maison Blanche attack.
Belkacem was charged with helping him carry out the Musee d'Orsay bombing.
The prosecution case relied on a metro ticket which showed that Belkacem had left a nearby station before the Musee d'Orsay blast and Bensaid's fingerprints on a bomb fragment.
But it suffered a setback when the main prosecution witness, a policeman on the train, failed to identify Bensaid.
Third man
However, it appears that there was enough testimony from other evidence and circumstantial evidence to convict the two men.
GIA said it carried out the bombings to punish France for supporting the Algerian Government in its war on Islamic rebels.
A third man accused over the attacks, Rachid Ramda, 33, has been held in London since 1995, but his extradition has been blocked by UK courts.
Judges in Paris are expected to try him in absentia.