Haussmann's renovation of Paris
Once the fighting began inside Paris, the strong neighborhood loyalties that had been an advantage of the Commune became something of a disadvantage: instead of an overall planned defence, each "quartier" fought desperately for its survival, and each was overcome in turn. The webs of narrow streets that made entire districts nearly impregnable in earlier Parisian revolutions had in the centre been replaced by wide boulevards during Haussmann's renovation of Paris. The Versailles forces enjoyed a centralised command and had superior numbers. They had learned the tactics of street fighting and simply tunnelled through the walls of houses to outflank the Communards' barricades.