respectively corresponding to years: $1789, 1826,
1836, 1888, 1999, 2010$. For each time, we constructed the associated primal graph $G_t$ (see the Methods section and  [@Barthelemy:2011; @Strano:2012]), i.e. the graph where the nodes represent street junctions and the links correspond to road segments. In particular, it is important to note that we have thus snapshots of the street network before Haussmann works (1789-1836) and after (1888-2010). This allows us to study quantitatively the effect of such central planning.

In Fig. \[fig:maps\](a), we display the map of Paris as it was in 1789 on top of the current map (2010).

In order to use a single basis for comparison, we limited our study over time to the portion corresponding to 1789. We note here that the evolution of the outskirts and small villages in the surroundings has certainly an impact on the evolution of Paris and even if we focus here (mainly because of data availability reasons) on the structural modifications of the inner structure of Paris, a study at a larger scale will certainly be needed for capturing the whole picture of the evolution of this city. We then have 6 maps for different times and for the same area 