The 24-year-old central defender has been told by his French club that he can leave the Felix Bollaert, after falling to make an impression on Joel Muller's first team.
Barul arrived at Lens in 2000 from Cannes, but after only playing 17 games in the last two years, he has failed to feature this year and is now looking to kick-start his career in England.
The Frenchman will arrive at Deepdale this week to try and impress North End boss David Moyes.
Meanwhile, Lens have completed the signing of Marseille defender Zoumana Camara in exchange for striker Lamine Sakho.
