Reports earlier this week claimed Chelsea scouts had made the trip to the Stade Velodrome for the Champions League tie against Borussia Dortmund with the intention of watching Thauvin.
And it's since emerged that Manchester United also had officials in attendance, scouting the highly-rated 20-year-old attacking midfielder.
The former-Bastia star joined Lille in January, was sent back on loan to Bastia for the reminder of last season, before moving to Marseille in the summer for €15m without having played a league match for Lille.
He's since made 13 Ligue 1 appearances for his new club, scoring four goals, but is already being linked with a move to the Premier League.
Manchester United, Manchester City, Chelsea and Aston Villa have all been heavily linked with the France under-21 international.
He's been impressive for Marseille over the past few weeks after a slow start, with goals against Napoli, Sochaux, Ajaccio and Montpellier since the beginning of November.
And Marseille team-mate Mathieu Valbuena has backed Thauvin for a full France national team call-up if he continues this rich vein of form.
United and Chelsea are expected to strengthen in January, with both Premier League sides in need of reinforcements to push for a title challenge.
United have been criticised for their lack of creativity in the middle of midfield, with Chelsea thought to be targeting at least one new striker next month.