De Telegraaf says City scouts joined representatives from Borussia Dortmund to check on Kongolo in weekend action in the recent Europa League tie with HNK Rijeka. Also present was BVB sports director Michael Zorc.
Kongolo's kid brother, Rodney, is already on the books at City, where manager Manuel Pellegrini has long-term defensive concerns.
Louis van Gaal's Manchester United have also been linked with Kongolo this season.
Van Gaal surprised Dutch pundits by taking Kongolo with him to the World Cup this summer.
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