According to this general system, Paris, under the direction of General Haxo, was, on the northern side, placed in a complete state of defence, by a double line of fortifications, so that, if the first were forced, the defenders might retire within the second, instead of being compelled, as in the preceding year, to quit the heights and fall back upon the city. Montmartre was very strongly fortified. The southern part of the city on the opposite side of the Seine was only covered with a few field-works; time, and the open character of the ground, permitting no more. But the Seine itself was relied upon as a barrier, having proved such in 1814. On the frontiers, similar precautions were observed. Intrenchments were constructed in the five principal passes of the Vosgesian mountains, and all the natural passes and strongholds of Lorraine were put in the best possible state of defence. The posts on the inner line were strengthened with the greatest care. The fine military position under the walls of Lyons was improved with great expense and labour. A _tête-de-pont_ was erected at Brotteau; a drawbridge and barricade protected the suburb la Guillotière; redoubts were erected between the Saonne and Rhine, and upon the heights of Pierre Encise and the Quarter of Saint John. Guise, Vitri, Soissons, Chauteau-Thierry, Langres, and all the towns capable of any defence, were rendered as strong as posts, palisades, redoubts, and field-works could make them. The Russian armies, though pressing fast forward, were not as yet arrived upon the line of operations; and Napoleon doubtless trusted that these impediments, in front of the Austrian line, would arrest any hasty advance on their part, since the well-known tactics of that school declare against leaving in their rear fortresses or towns possessed by the enemy, however insignificant or slightly garrisoned, or however completely they might be masked.