Social workers in Cologne have been giving migrants special training to prepare them for the city's traditional, and boisterous, Carnival celebrations.

The effort comes in the wake of a string of robberies and sexual assaults on New Year's Eve in the city that police say were committed largely by foreigners.

German authorities are keen to avoid a repeat of those events during the five-day street party starting Thursday.

Caritas, a Catholic welfare association, hosted a lecture Tuesday for 150 migrants who got a crash course from teachers dressed in costumes and with performances by local musicians.

Hundreds of thousands of revelers are expected to party on the streets and in the city's pubs and bars until Ash Wednesday.