Adlène Hicheur, who worked at the CERN research centre in Geneva, Switzerland, is on trial in Paris on charges of criminal association as part of a terrorist entreprise.
Police arrested him after intercepting emails he wrote to an alleged al-Qaeda contact.
Hicheur has spent the past two years in custody awaiting trial.
His lawyer Patrick Baudouin said of the e-mail exchange:
"The prosecutor tried to prove those words were actually showing an intention to concretely act, helping to prepare or directly preparing a terrorist action. This is exactly what I contested, because Adlène Hicheur's words hadn't mentioned any precise planning of anything in particular."
When asked by euronews if police had identified the alleged Al-Qaeda contact, he said:
"This person has not been formally identified, but throughout the investigation they said it appears to be Mustapha Debchi, who is allegedly a senior member of Al-Qaeda in the Islamic Maghreb, based in Algeria. "But if you are sure about his identity, you don't say 'it appears to be' -- you say it is that person in question."
Hicheur's trial comes more than one week after French president Nicolas Sarkozy proposed to make repeated surfing of extremist websites a criminal offence following the Toulouse shootings.