According to journalist Graeme Bailey, the Premier League club have been following the emergence of the 20-year-old centre-back, who has established himself as an attractive prospect in France.
Aït Boudlal's performances have already attracted significant interest. Fulham reportedly tested Rennes' resolve during the summer with a €30 million offer for the defender, but the proposal was rejected.
Newcastle United would therefore face a substantial financial commitment if they decide to turn their interest into a formal approach.
The Magpies are looking to make the most of the resources available to Jaissle, and Aït Boudlal has emerged as one of the young defenders being considered as the club assesses its options.
For now, Newcastle's interest remains at the monitoring stage, with no indication in the source that a formal bid has been made.
The €30 million proposal from Fulham nevertheless provides an indication of the level at which Rennes could value the Morocco international, meaning Newcastle would likely have to make a significant investment to prise him away.