The suspected ringleader of the Paris attacks was near the Bataclan theatre during a siege there, prosecutors say.
Prosecutor Francois Molins said mobile phone data also showed Abdelhamid Abaaoud returned to cafes and restaurants targeted in the attacks.
He added there was evidence that Abaaoud was planning an attack on Paris’s La Defense business district.
Meanwhile an arrest warrant was issued in Belgium for a man named Mohamed Abrini over the attacks.
Abaaoud was known to have himself taken part in the shootings at the bars and restaurants in Paris, before driving out with a probable accomplice to a suburb and abandoning their car.
A timeline has now started to emerge of what happened then, and in the days afterwards.
- Mr Molins revealed on Tuesday that Abaaoud is then thought to have returned by metro to the scene of the crime
- Abaaoud then spent two days in the northern Paris suburbs before finding the flat in the suburb of Saint-Denis with help from his cousin, Hasna Ait Boulahcen
- The two of them, and an unidentified third person who police now believe was probably his accomplice gunman on the night of the attacks, died in the police raid on the flat on 18 November
- Investigators say they have evidence that, had the group not been cornered, they were planning to carry out suicide bomb attacks last Wednesday and Thursday in the La Defense business district
Also on Tuesday, Jawad Bendaoud, the man who lent the Saint-Denis flat, was put under formal investigation for “criminal conspiracy in connection with a terrorist enterprise”.
Also on Tuesday, Belgian prosecutors said that two days before the attacks, new suspect Mohamed Abrini was seen driving a car with suspect Salah Abdeslam at a petrol station on the motorway to Paris.
Abrini is described as “dangerous and probably armed”.
Abdeslam is currently the subject of an international manhunt after the attacks which killed 130 people.
The Renault Clio that Abrini was seen driving was later used in the attacks, prosecutors say.
Police say he should not be approached by the public.
Belgian prosecutors also said on Tuesday that they have also partially identified two other men who have been taken into custody.
They are under suspicion – in the words of a statement – of “participating in the activities of a terrorist group”, and “acts of terrorist murder”.
The men, named as Ali O and Lazez A, are both from the Brussels district of Molenbeek, and both will appear separately in court during the course of this week.
Also on Tuesday, French President Francois Hollande met US President Barack Obama in Washington where the two leaders re-iterated their commitment to eradicating the so-called Islamic State (IS) group, which said it carried out the Paris attacks.
Mr Obama said there would be increased co-operation with France to hit IS targets in Iraq and Syria, and called on the EU to finally implement an agreement that would require airlines to the share passenger information.
Hours after the two men spoke, French warplanes hit an IS command centre in the Iraqi city of Tal Afar, according to French officials.