German academic Hans Werner Gottinger, whose penchant for inventing academic affiliations to promote his career was exposed by Nature last year, seems to be up to his old tricks.

This week, the German environmental economist was to run a 15-hour workshop for the Belgian organization Eurosis, at the University of Porto in Portugal. But the workshop was abandoned after the Ostend-based organization, which runs conferences and services promoting modelling and simulation, discovered that Gottinger was not the university professor he claimed to be.

Gottinger told Nature last August that he was in 'semi-retirement' (see Nature 448, 632–633; 2007). But when he applied to run the Eurosis workshop just a few months later, he claimed to be a professor at the Technical University of Munich in Germany — specifying that he was director of the STRATEC Institute. The university says that it has never employed him and does not host such an institute. It is considering whether to take the matter beyond a formal request to desist.

Eurosis had accepted Gottinger's proposal, which was included in the organization's annual Future Business Technology conference, on 9–11 April. Philippe Geril, secretary-general of Eurosis, says that at the beginning of March, the University of Porto alerted the organization to potential problems. Gottinger withdrew from participation when Geril asked for more details of his affiliation. Gottinger did not respond to Nature's request for clarification.

Gottinger has held many real academic appointments at top universities and research institutes, but frequently used false claims on his CV to acquire them. He has also been accused of extensive plagiarism, including 13 confirmed cases.