Singo, whose shot had been blocked, tried to jump over the sliding Donnarumma but instead struck his face.
Donnarumma walked away to be replaced by Matvey Safonov after being hit on face by the cleat of Wilfried Singo in the 17th minute.
Paris Saint-Germain goalkeeper Gianluigi Donnarumma's face was bloodied after being hit by an opponent's cleat in a French league game against Monaco on Wednesday.
The Italy international took the studs of Wilfried Singo's cleat in the 17th minute at the Stade Louis II.
Singo, whose shot had been blocked, tried to jump over the sliding Donnarumma but instead struck his face.
Pictures showed that Donnarumma was cut below his right eye. Singo, who had already been warned, was lucky to avoid a red card.
Donnarumma was left lying on the pitch while receiving treatment. He finally stood up and walked away to be replaced by Matvey Safonov.