This study examines linguistic change as it is found in the works of Daniel Pennac. It discusses heterogeneity at different levels--phonetic, lexical, syntactical, and stylistic--which leaves traces in the language itself of the mixture of different races and cultures, and is highlighted by the microcosm of the neighborhood of Belleville in Paris. Such social and cultural heterogeneity, which imposes linguistic changes to the language due to racial coexistence, reflects a period of transition, the end of the 20th century, and encourages tolerance by infusing to French language a new creative flavor. (Contains 12 references and 43 notes.) (Author/VWL)