Complex sentence: In the autumn of 1861, young Grigorescu leave for Paris, where he studied at th Belle-Arte School, in the meantime he attended the workshop of Sebastien Cornu, where he had as colleague Pierre-Auguste Renoir.
Split into simpler sentences: In the autumn of 1861, young Grigorescu left for Paris, where he studied at the Belle-Arte School. He also attended the workshop of Sebastien Cornu, where he had as a colleague Pierre-Auguste Renoir.