The paper compares two sites that have recently been included by Unesco in the World Heritage List - La Chaux-de-Fonds/Le Locle and Nice - by focusing on the ways in which histories of early nineteenth-century planning have been mobilised in the construction of public narratives associated to urban heritage. Although such narratives appear to be questionable in many respects when confronted with available documentary evidence, they also seem capable to play a fruitful role in fostering the emergence of new research on hitherto underexplored topics. They therefore provide an interesting observation ground to explore the mutual links that potentially exist between academic urban histories, on the one hand, and socially shared accounts of urban change, on the other hand. When observed side by side, these Unesco sites point at the need for a comparative re-assessment of the history of early nineteenth-century gridiron-based city plans, especially within Napoleonic Europe. Once understood as the outcome of implicit urban theories valuing rational organization, individual initiative and an equal distribution of opportunities, these plans have in fact nourished a remarkable plurality of social imaginaries - well exemplified here by the opposition between plans conceived as a support for international tourism and leisure activities along the French seaside, and a plan conceived as a support for industrial production in the Swiss mountains.
Keywords: Public History, Unesco, Urban Heritage, Early Nineteenth-Century Urban Planning, Comparison.