Since graduating from the MA Photojournalism and Documentary Photography at the London College of Communication in 2014, Mathieu has worked extensively in South East Asia, covering mainly Myanmar, Thailand and Hong Kong. Mathieu also attended the XXVI Eddie Adams Workshop. He started his career whilst interning at the VII Photo agency in Paris in 2012. During that summer, he shot his first assignments for The New York Times. Mathieu's work has been published in the New York Times, the International Herald Tribune, L'Espresso, Al Jazeera, CNN.com, Mashable and the Sunday Times.