He continued his composition studies with Michael Jarrell at the Geneva University of Music in 2005–2006, and with Jonathan Harvey, Brian Ferneyhough, Beat Furrer and Philippe Manoury at IRCAM, Royaumont foundation academy, Centre Acanthes (France) and Takefu (Japan).
He has received commissions from the French state, from the IRCAM-Centre Pompidou on seven occasions, from the Spanish ministry of culture, from the government of Catalonia, from the City Council of Munich for the Munich Biennale and from institutions such as Academy of Arts, Berlin, Musée du Louvre, WDR, SWR, Kölner Philharmonie, Auditori de Barcelona, Ensemble Intercontemporain, Klangforum Wien/Impuls academy Graz, Strasbourg Music Festival, Orchestre national d'Île-de-France, IVM (Valencia), Musica de Hoy (Xavier Güell), Schauspielhaus Salzburg, Caja Madrid or the Selmer Society (Paris).
But his interest also includes more contemporary artists such as sculptor Jaume Plensa (who contributed in the making of the choir piece Breathing with a piece of poetry), Matthew Ritchie (who Parra worked with for Hypermusic Prologue and Hypermusic Ascension,[8] exhibited in New York's Guggenheim Museum), Antoni Tàpies (Cos de matèria), Gordon Matta-Clark or Gregor Schneider (Haus u r / Office Baroque, Wilde).
He transferred theories from theoretical physicist Lisa Randall, astrophysicist Jean-Pierre Luminet or organic chemist and molecular biologist Graham Cairns-Smith into musical processes, leading him to small chamber pieces, orchestra pieces and eventually also to his opera Hypermusic Prologue based on a libretto by Lisa Randall.
The opera Das geopferte Leben with a libretto by Marie NDiaye was premiered by the Freiburger Barockorchester and the ensemble recherche at the Munich Biennale in 2014.
[9] In the succeeding year the opera Wilde was premiered at the Schwetzingen Festival,[10] with Calixto Bieito as director and a libretto by Klaus Händl.