precisely these new links, we use the betweenness centrality impact $\delta$ defined in [@Strano:2012] and which measures how a new link (absent at time $t$ and present at time $t+1$) affects the average betweenness centrality (see Methods section for definitions of the betweenness centrality impact $\delta$). In [@Strano:2012], the distribution of this quantity displays two peaks which corresponds to two types of links belonging to two distinct processes: densification and exploration [@Strano:2012]. We first observe (see Figure 2 of SI) that in the first period, the majority of new links are of the $E_2$ type and correspond to construction of new streets with new nodes. We see that the Haussmann transition period (1836-1888) is not particularly different from the other previous periods. In the modern period (after 1999), $E_0$ becomes dominant and consistent with the idea of a mature street network where densification dominates the evolution of the urban tissue. Obviously, this is also an effect of limiting ourselves to the 1789 portion: in a wider area, many new roads were created and both densification and exploration coexist. We note here that the structure of the street network of central Paris remained remarkably stable from 1888 until now (and in 