Dogaru, Darie and another man, Alexandru Bitu, who played a lesser role in the theft, admitted they took the paintings from the Kunsthal in October 2012.
The stolen paintings included Pablo Picasso's 1971 "Harlequin Head," Claude Monet's 1901 "Waterloo Bridge, London," Henri Matisse's 1919 "Reading Girl in White and Yellow" and Paul Gauguin's 1898 "Girl in Front of Open Window."
The works have never been found. Dogaru's mother added a twist to the case by telling prosecutors that she burned the paintings then retracted her statement.
The trial will continue for Dogaru's mother Olga, who is charged with destroying the works. Three others, including Bitu, are also on trial, and their court case will resume on Dec. 3.