Giovanni Troilo on Wednesday lost his first prize in the contemporary issues category following an investigation into his photo series, entitled La Ville Noir – The Dark Heart of Europe.

In his submission Troilo claimed all ten of the winning photographs were taken in Charleroi, a Belgian city known in the past for its crime and prostitution, but further investigation revealed one of the shots was taken in Brussels.

The photographer admitted falsifying information about the photograph in question, of a painter and live models, prompting the World Press Photo foundation to disqualify the work.

An investigation into Troilo’s images came after a complaint from Charleroi’s mayor, who said the series was a “serious distortion of reality” about his city.

Among the mayor’s complaints was that one of the images, of an overweight man at home, demonstrated “neurotic obesity”. The subject, Philippe G, however said he was proud of his body and happy to pose topless for Troilo.

Questions were also raised about an image depicting the photographer’s cousin having sex in a car.

Although Troilo’s relative had given the photographer permission to follow him and shoot the scene, World Press Photo said this did not amount to staging as the couple would have sex in public with or without the photographer being present.

After the initial complaints, World Press Photo on Sunday confirmed Toilo’s award and said there were “no grounds for doubting the photographer’s integrity in carrying out his work”.

Fresh information, however, prompted the foundation to reopen its investigation on Tuesday, revealing one of the images was not shot in Charleroi.

Discussing the decision to disqualify Troilo, Lars Boering, World Press Photo’s managing director, said in a statement that “a rule has now been broken and a line has been crossed”.

“The World Press Photo Contest must be based on trust in the photographers who enter their work and in their professional ethics. We have checks and controls in place, of course, but the contest simply does not work without trust.

“We now have a clear case of misleading information and this changes the way the story is perceived,” Boering said.

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