Why did Charles Marville photograph both old and new Paris?

Charles Marville photographed both old and new Paris because he was officially hired by the city of Paris to create an encyclopaedic record of the massive urban planning project led by Baron Georges-Eugène Haussmann.1

While photographers like Eugène Atget were driven by a personal, artistic mission to document the vanishing remnants of old Paris, Marville’s work served a specific administrative purpose. His commission required him to capture the transformation of the city as it unfolded, documenting both the existing structures and the new, modernized landscape created by Haussmann’s wide avenues and infrastructure improvements. Consequently, Marville’s images functioned as a systematic visual archive of the city's radical physical evolution.12