Electoral maps are one of the main tools used to analyze French elections, but scales most commonly used (commune, canton, department) do not allow investigation of urban behavior which nevertheless constitutes the main part of voting people. The objective of the Cartelec project was firstly to built, then to give access to a large audience, on data and electoral maps on polling station level for all French cities larger than 20 000 inhabitants for the period 2007-2012. The challenge is both scientific - urban electoral behavior remains largely unknown and is often limited to unproven stereotypes (gentrified neighborhood voting for greens while peripheral ones abstain or choose extreme parties) - and citizen - giving access to results on the finest aggregation level available can improve citizen participation on political life. Comparing electoral data with demographic, sociological and economic data on this analysis scale allows a better understanding of electoral behavior in urban spaces and of political and spatial segregation.
