Complex sentence: Paul spent his 21 first year growing up in Plaisir, Yvelines and Paris, France, where he studied to become a biological engineer but then in 1991 decided to attend Berklee College of Music in Boston in the Music production and engineering departement.
Split into simpler sentences: Paul spent his 21 first years growing up in Plaisir, Yvelines and Paris, France, where he studied to become a biological engineer. In 1991, he decided to attend Berklee College of Music in Boston, focusing his studies in the Music production and Engineering departement.