Police are searching a rural area in northern Germany after being tipped-off that Salah Abdeslam may be hiding out near Hanover.
Bielefeld police say a member of the public provided information suggesting Abdeslam was staying at an address in Minden-Luebbecke, some 55 miles from Hanover.
Officers are carrying out an "intensive investigation" in the area but are yet to find any sign of the 26-year-old fugitive.
Authorities believe Abdeslam crossed into Belgium the day after the Paris attacks, which killed 130 people and wounded hundreds of others.
Investigations are also continuing in Brussels, which remains under lockdown following a weekend terror alert.
Earlier police discovered a suicide belt in a dustbin in the Paris suburb of Montrouge, where phone location data has placed Abdeslam on the evening of the attacks.
Italian authorities have also confirmed that Abdelsam and another suspected Islamic State militant travelled through Italy three months prior to the attacks.
Interior minister Angelino Alfano said Abdeslam and Ahmad Dahmani caught a ferry from the southern port of Bari to Greece on 1 August.
They returned to Bari from Greece on 5 August, and crossed Italy by car before reaching France on 6 August.
Mr Alfano said that "when they made the crossing they were free citizens, not sought-after terrorists".
Abdeslam is suspected of playing at least a logistical role in the coordinated shooting and suicide bombings in the French capital on 13 November.
The fugitive's brother Mohamed has suggested that Abdeslam may have decided not to go ahead with his attack at the last moment.
Another theory put forward by police is that Abdeslam, if he was involved in the attacks, may have had a technical problem with his suicide belt.
Abdeslam's other brother, 31-year-old Brahim, died after his suicide belt exploded outside a cafe during the attacks, injuring 15 people.