After missing out on big name targets Pedro, Thomas Muller, Neymar and Gareth Bale, United made a move for the 19-year-old who has been likened to Thierry Henry.
French newspaper L'Equipe's headline says "Plus cher que Zidane" which translated means "more expensive than Zidane".
Surprise at Anthony Martial's move to Man United reflected on front page of @lequipe: 'MORE EXPENSIVE THAN ZIDANE' pic.twitter.com/jAROeHjcxz
The daily poses the question: "Where is the sense in the transfer market when an uncapped 19-year-old kid, 11 goals in 52 games, costs as much as Zidane at his peak?"
Sources at Old Trafford say the deal could rise to £50m after add-ons and bonuses but reports in France suggest the fee could reach £58m (€80m).
In 2001, Real Madrid paid €75m to sign Zidane from Juventus.
GETTY
Anthony Martial should complete his move to Manchester United today
Meanwhile journalist Philippe Auclair says people in France can't believe how much United are paying for Martial.
"Is he worth that amount of money? If you ask the people back in France they will say no he's not," Auclair told Radio 5 live.
"This amount of money leaves people speechless in France.
"He's still a very raw product, we don't yet know how far Anthony Martial will go."
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