
He is also a sought-after chamber musician, and with the Klarthe Quintet, he won the 3rd Prize, the Palazetto Bru Zane Prize for the interpretation of Georges Onslow’s Quintet Op. 88, as well as the Bayerische Rundfunk Klassik Online Prize at the ARD International Competition in Munich in 2014. Klarthe Quintet released their first album, French Touch, in 2016 under the Klarthe Records label.
Finalist of the Jean Françaix International Competition in 2004, ADAMI Classical Revelation in 2008, and laureate of the ARD International Competition in Munich in 2013, he also performs as a soloist, notably with the Mulhouse Symphony Orchestra and the Münchner Kammerorchester.
Guillaume has been the principal bassoonist of the Mulhouse Symphony Orchestra and bassoon professor at the Conservatoire à Rayonnement Départemental of the city since 2008.