Mathieu is responsible for the International Business Advisory Services department (IBAS) dedicated to assisting global companies in their international development working both in and out of France. He heads a team for Grant Thornton France which deals with all matters concerning local compliance (bookkeeping, tax, payroll, reporting, statutory accounts) and helps his clients grow internationally (coordinating services, connecting with other member firms and financial advisory). His team has developed strong foreign desks for China, Japan, Canada and Germany, and counts people from more than 10 nationalities.