According to The Guardian, United have now joined the race for the Ivory Coast international as they look to beef up one of their arguably weakest areas - central midfield.
The news comes as United look increasingly likely to secure the transfer of Arsenal's Alexis Sanchez from under the noses of the Sky Blues, who appeared to be favourites ever since the failed deadline day move in the summer.
Although City's unbeaten run was recently ended by Liverpool's 4-3 victory at Anfield, their midfield is arguably where everything ticks with the likes of Kevin De Bruyne, David Silva, Ilkay Gundogan and Fernandinho all putting in world class performances this season.
With Fernandinho turning 33 in May, Seri could be viewed by Guardiola as a possible replacement for the Brazilian as he has a similar rugged box-to-box play style.
City, who have also been linked with Shakhtar Donetsk's Fred, are hoping to sign a new midfielder in the summer but will have to be wary of a similar Alexis hijacking situation with Seri, if they wait too long. Liverpool are also looking for a new name in the centre of the park as doubts remain over the future of Emre Can, and following the departure of Philippe Coutinho to Barcelona.
The Nice midfielder has less than 18 months on his contract after his move to Barcelona in the summer fell through leaving him devastated and struggling for form this season.
He won the Marc-Vivien Foé trophy for the best African player in France last year and could replace his compatriot Yaya Toure at the Sky Blues as his career looks to be coming to an end.
City have entered initial talks with Seri's representatives this week but will have to cough up £35m to get their man despite his contract coming to an end soon.
United had scouts to watch Seri assist Mario Balotelli in Nice's 2-2 draw with Monaco last week so both sides are definitely interested in the 26-year-old, it just depends whether he chooses red or blue.