This paper successively examines two fundamental issues that toponymy, as an identity reference, presents. Following an overview of the recent developments in toponymy which led to its recognition as an autonomous transdisciplinary science, this paper proceeds to identify the identity paradoxes that stem from all attempts to create a thorough inventory of a toponymy based on language and culture in a shared multilingual territory. A typology of the obstacles that hamper the identification of geographical names vis-à-vis a target culture is proposed. This process of analyzing how any attempt to address the exhaustive nomenclature of a cultural heritage identified through toponymy illustrates the unravelling of a rich diversity marked by interculturality. In order to better explore this phenomenon, the paper examines the obstacles encountered while compiling the inventory of the 2,500 toponyms of French origin and French influence in Saskatchewan, a province located in central Canada. These toponyms are examples of said process.