Sow, 25, is the leading scorer in French Ligue One this season with 21 goals and his side lead champs Marseille by one point in the title race.
The Senegal star has hit the big-time after four indifferent seasons at Rennes.
Lille will drive a hard bargain for their most prized asset as they are keen to keep hold of him for at least one more season.
Magpies chief scout Graham Carr watched Sow in last week's defeat at Monaco.
Newcastle are willing to go to £15 million for the striker, says The Sun.