Guillaume studied Jazz double bass in Nice Conservatoire (FR) and continued in Amsterdam Conservatorium where he graduated. He had the opportunity to attend masterclasses with Kurt Rozenwinkel,  Brad Meldhau, Wynton Marsalis, Larry Grenadier, John Patitucci, Brian Blade, Ari Hoenig, Peter Erskine and more.

From 2005 to 2006 he has been performing and hosting 2 jazz concerts on a weekly base at l'Authentic restaurant Nice(FR). From 2007 until 2009 he hosted and performed 2 jazz concerts per week at Proef Amsterdam (NL). From 2009 until 2020 Guillaume has been hosting and performing live music in Gollem's Proeflokaal in Amsterdam (NL) every Saturday where he played with great musicians from the Netherlands.

in 2009 Guillaume was selected to the semi final of the “Keep an eye” jazz award with his own compositions and his own project. In the following he recorded 3 of his compositions.

Between 2007 and 2018  he has been playing as a free lancer or as an active band member musician in several projects performing and touring in France, Belgium and the Netherlands. Band member ship with: Wouter Penris band, Amsterdam Quartet, Purple Gazelle, Wet Dogs Trio, Medine Bouma Trio. Free lancer collaboration with: Benjamin Herman, Jerome Hol, Tineke Postma, Jamie Peet, Tim Welvaars, Erik Kooger, Sanna van Vliet, Daniel de Moraes, Thijs Kuppen, Steve Altenberg, Baas van Lier, and many more.

 Currently: producing music,  and is an active band member with : 

.The WetDogs Trio alias KoMoGo Trio : Daniel de Moraes on guitar, Erik Kooger on Drums.

. Gole Gole: Daniel de Moraes on guitar and Brancka on vocals.

.Purple Gazelle, a tap dance - jazz project with Marije Nie tap-dancing and a jazz trio with Erik Kooger and Christian Pabst. The project plays some of the best repertoire of Duke Ellington with an adding of our wild and delicate improvisations.

 

Festival performances:

. UITmarket festival Amsterdam 2008: G.Ortet Band with own composition

. UITmarket festival Amsterdam 2009: G.Ortet & Franz von Chossy Duo

. Meer jazz festival Almeer 2009: G. Ortet band with own compositions.

. Bevrijdingsfestival Zwolle 2011: Sir Randall – Positieve Energie

. Red-light festival  Amsterdam 2014: Alex Rossi plays Jobim project

. Red-light festival  Amsterdam 2015: G.Ortet - D.de Moraes - E.Kooger

. Meer Jazz festival Almeer 2016: with Olaf Keus Quintet

         Teaching:

        He his currently teaching @:

. Leerorkest Netherlands as a double-bass and cello teacher for classical orchestra for children in primary schools: https://www.leerorkest.nl/nl/home

. Music for life Amsterdam: http://music4life.nu/

. Private lessons at home