Borussia Dortmund CEO Hans-Joachim Watzke says that it is "unfair" that Paris Saint-Germain have signed Lionel Messi.

PSG unveiled Messi on Wednesday following his free transfer move from Barcelona on a bumper two-year deal.

Watzke, who has had to ward off strong interest in Dortmund's prized asset Erling Haaland this off-season, said Qatari-owned PSG's economic position was unfair.

“It is a fact that PSG has more economic resources than 85 per cent of other European teams," Watzke said as reported by L'Equipe.

"It is clear that this is an unfair competition that has already been rife for too long but I am by no means jealous.

"Frankly, it wouldn't be my cup of tea to have to kneel down every fourth morning in front of the Emir of Qatar."

PSG have signed Messi along with Georginio Wijnaldum, Sergio Ramos and Gianluigi Donnarumma on free transfers this off-season, bumping up their player wages.

The Parisians also spent €60million to sign Internazionale full-back Achraf Hakimi, having purchased Mauro Icardi for the Nerazzurri 12 months ago for €50m.