Gildard GUILLAUME took the oath in 1970. During his national service, he taught law and political sciences at the National Administration School of the Republic of Niger. He first collaborated with a business lawyer firm till 1977. He then founded his own office. In 2002, he founded GILDARD GUILLAUME & ASSOCIES firm with his colleague Nathalie BAUDRY.

He graduated from University with the Diplôme d'Etudes Supérieures de Droit Privé, the Diplôme de l'Institut du Droit des Affaires, the Certificat d'Etudes Judiciaires and the Certificat du Centre Universitaire d'Etudes des Communautés Européennes. He also graduated from the Centre de Perfectionnement aux Affaires (now CPA Executive MBA Groupe HEC) and also followed the financial course given by CESA FINANCE (HEC MANAGEMENT).

He received specialized certificates in « Commercial, Business and Competition Law » and in « Estate Law ».

Last, he has also followed a course on mediation methods.

He most particularly manages business agreements negotiation, patrimonial choices, conflicts between business partners or part owners, acquisitions, real estate disorders, competition and branding questions, criminal business law, funds, liberal professions liability, corporation law, car sales, commercial representation and cooperative agreements.

Besides law, Gildard GUILLAUME largely contributes to the cultural action. Member of the board of directors of the Institut Napoléon, he participates in many events regarding historical research, writes articles and publishes books. He also cares for the architectural heritage and currently presides a fund dedicated to a historical monument restoration.