The rally Sunday was organized by the father of one of the victims, Pravda reported Monday.
The mass demonstrations were called Sunday to protest the early release of Michelle Martin, an accomplice of Marc Dutroux, sentenced to life in prison in June 2004 for the kidnap and rape of six teen and pre-teen girls in the 1990s.
Martin, 52, has been behind bars since 1996 and was convicted in 2004 of being Dutroux's accomplice in the deaths of two girls.
The couple since divorced.
Notable deaths of 2014 [PHOTOS]