The Thiers wall () was the last of the defensive walls of Paris. It was an enclosure constructed between 1841 and 1846 and was proposed by the French prime minister Adolphe Thiers but was actually implemented by his successor, Marshal Soult. The long wall and ditch made a complete circuit around the city as it stood at the time of the July Monarchy. It was bombarded by the Prussian Army during the Franco-Prussian War, captured by government troops during the Paris Commune and refortified at the start of the First World War. However, by then it had become obsolete as a fortification and was a barrier to the expansion of the city. The area immediately outside of it, known as "the zone", had become a shanty town. The wall was demolished in the interwar period; its path today can be traced by the Boulevards of the Marshals which originally ran just behind the fortifications and by the Boulevard Périphérique which was later built just outside. A few remnants of the wall can still be seen.
Background
By the mid-16th century, Paris was defended by walls which had been built and rebuilt over the preceding centuries, but apart from the latest additions were largely obsolete for modern warfare and enclosed too small an area to contain the growing suburbs. In 1670, King Louis XIV ordered the demolition of all the walls surrounding Paris on the grounds that France was militarily secure and that a modern system of border fortifications had been constructed at great expense, and that like London and Madrid, Paris had become too large to fortify. Following the course of the demolished walls, the first boulevards were laid out, wide tree-lined avenues whose name is the French word for "bulwark".Pollak 2010, p. 190 An ambitious scheme of fortification for Paris proposed in 1689 by France's leading military engineer, Marshal Sébastien Le Prestre de Vauban, was not proceeded with. Following the Battle of Paris in 1814, when the Coalition armies had captured the city after a single day's fighting, there was renewed political pressure for the capital to be fortified. A royal commission for the defence of the kingdom considered the issue between 1818 and 1820, finally recommending a detailed plan of defences in the following year, but it was never implemented.Papayanis 2004, pp. 105-106
Planning When Louis-Philippe was proclaimed king of the French in 1830, there was renewed interest in the issue. A further commission on the defence of the kingdom first met in 1836 and by May 1838 began to consider the defence of Paris. After much debate, it was decided that the capital should be fortified in two ways; by a continuous wall which could be manned by the National Guard and would prevent infiltration or a surprise attack, and further out from that, by a chain of detached forts manned by the regular field army, which could prevent an enemy from establishing positions from which they could bombard the city and create a line so long that it would be difficult for besiegers to enforce a tight blockade. A further point in favour of this dual approach was that regular troops would not come into close contact with the notoriously rebellious Parisians, which might lead to a loss of discipline.Cox 2019, pp. 131-133
Implementation
On 1 March 1840, Adolphe Thiers returned to office as prime minister and soon war threatened over the Oriental Crisis, when France found itself in opposition to Britain and Austria over events in Egypt. He was therefore amenable to an approach by the Duke of Orléans and François Chabaud-Latour to implement the commission's recommendations to fortify Paris. Chabaud-Latour was an army officer who had worked on the commission's plans and was also a deputy in the National Assembly. Thiers obtained the backing of his cabinet for the scheme while the deputies were away on holiday, but then found there was fierce resistance from the left, led by François Arago and Alphonse de Lamartine, who suspected that the government had ulterior political motives: that the fortifications, especially the detached forts, were intended to threaten the Parisians in case of a revolt against the monarchy. Other arguments suggested that by making Paris a fortress, it would make the city an irresistible objective for any invading army. Thiers was forced to resign over foreign policy in October, but his successor, Marshal Soult, was determined to press on with the plan. Debate began in the legislature in January 1841 and the necessary legislation was passed on 3 April.Papayanis 2004, pp. 105-106
This legislation appropriated 140 million French francs for the work, including 17,970 million francs for land acquisition, 16,608 million francs for earthworks and 83,356 million francs for masonry.Lazare 1993, p. 132 It was also necessary to clear an area in front of the fortifications to ensure that there was an unobstructed field of fire. Initially, an area known as a zone non ædificandi ("building-free zone") of 974 metres was envisaged, which would have been laid out as public parkland; however the final solution was a zone of 250 metres beyond the ditch on which it was forbidden to erect anything except a wooden fence. Although landowners whose property was confiscated for the actual fortifications were paid compensation, there was nothing for those whose property lay within the zone and was thus devalued.Cannon 2015, p. 16
Construction
The construction of the new works were overseen by Guillaume Dode de la Brunerie, the inspector-general of engineers and chairman of the fortifications committee.LePage 2006, p. 178 The fortifications not only included a continuous defensive wall or enceinte around the capital, but also a line of sixteen bastion forts lying between 2 and 5 kilometres from the wall. Although designed for all-round defence, these forts, such as Fort d'Issy, were not positioned so as to be able to support each other, unlike the polygonal forts being built by the Prussians at that time.Hogg 1975, p. 99 The work was undertaken by military engineers and commercial contractors and used a workforce of 20,000 troops and civilians. The course of the works crossed through 13 suburbsCannon 2015, p. 16 and was completed in 1846.Jones 2005, p. 292
Description
The long main wall, colloquially referred to as "the fortress", consisted of 94 bastions. These were numbered counting anti-clockwise from Bastion No 1 on the right (northern) bank of the River Seine in the southeast of Paris, round to Bastion No 94 which completed the circuit on the opposite bank. For command purposes, the wall was divided into nine military sectors, each sector consisting of between eight and twelve bastions. The wall was pierced by 17 gates (French: portes) for routes nationales, or major roads, 23 secondary road crossings (French: barrières) for routes départementales, and 12 posterns for local access. The gates were closeable by barriers and acted as toll booths the collection of taxes and tariffs; some of the main portes were fitted with drawbridges. The wall was also pierced in five places by rivers and canals and later, eight railway crossing points were constructed. All these access ways made the wall harder to defend, but in peacetime, there were insufficient crossings for a major commercial centre which resulted in congestion.LePage 2006, p. 181
The enceinte wall itself was constructed following the system devised by Louis de Cormontaigne nearly a century previously. The rampart was composed of packed earth and revetted by a vertical scarp (or front face) wall of stone, topped by a broad earthen parapet. In front of this was a wide dry ditch, bounded on the far side by an earthen counterscarp which sloped at an angle of 45° and was not revetted. Extending out from the top of the counterscarp was the glacis, a ridge intended to defend the scarp wall from direct bombardment, but the slope away from the fortress was angled so as to allow the defenders to fire on any attacking troops. However, a United States Army commission who visited in 1856 noted that the glacis, which rose above the floor of the ditch, only partially protected the vulnerable masonry of the scarp wall. Originally, there was a covered way which passed along the top of the counterscarp below the crest of the glacis, but by 1856 this had largely been eroded away.Delafield 1860, pp. 197–198
The fortifications were serviced by the Rue Militaire ("military road"), circling the city directly behind the works. During the Second Empire, it was replaced by a railway line 100 meters from the wall, the Chemin de fer de Petite Ceinture ("Little Belt Railway"). In peacetime the railway would serve to transfer merchandise and passengers between the capital’s mainline railway stations. The Rue Militaire thus relegated to a secondary role, in 1861 the city secured the authority to rebuild it as a boulevard, which was fully completed only in 1939 and which came to be known as the Boulevards of the Marshals.
Military history Siege of Paris
In the enthusiasm of the declaration of war against Prussia in July 1870, there was little thought given to the defence of Paris, as it was assumed that the fighting would all be in Germany. In the thirty years since the construction of the wall and the outlying forts, the range of artillery had almost doubled, and there were many vantage points in the hills surrounding the city from which modern guns could dominate the fortifications. During August, work had commenced on a redoubt at Chatillon in an attempt to remedy the most obvious case, but otherwise little was done. However, once news of the French defeats at Spicheren and Wörth reached Paris at the beginning of August, work commenced in earnest.
Some 80,000 men were employed in clearing fields of fire in front of the fortifications, including felling many of the trees in the parkland of the Bois de Boulogne, the wood from which was used to build obstacles. Another 12,000 workers set about blocking or obstructing the gates to allow a minimum of traffic to pass.Fermer 2011, pp. 27–28 The openings for canals and aqueducts were blocked or closed with gratings. Dams were constructed in the Seine to allow the normally dry ditch of the wall to fill with water. A large number of redoubts, entrenchments and artillery batteries were built beyond the wall in an attempt cover any dead ground between the forts and to deny the high ground above them to the enemy. Immediately to the northeast of the wall, the area in front of Saint-Denis was flooded.Tiedemann 1877, pp. 127–129 On the wall itself, embrasures were cut into the parapets, traverses (embankments to protect against enfilade fire) were installed and shelters were constructed to protect against plunging mortar fire.LePage 2006, p. 199 The National Guard was expanded from 24,000 in Paris at the start of the war to 350,000 men, although Louis-Jules Trochu, the new president, quipped that "We have many men but few soldiers". In all the garrison numbered about half a million men, with 3,000 cannon of various types, many manned by naval reservists.Horne 2007, p. 62
When the Prussians arrived on 2 September, they began a wide encirclement of Paris starting from the southwest which was completed a week later when they had entrenched themselves on all the commanding heights, a front of some . The Prussian force was outnumbered, having some 240,000 men and 1,140 guns, so it was decided not to take the city by direct assault, but by bombarding the garrison into submission. Despite their numerical inferiority, the Prussians were able to defeat several sorties by the garrison; however, supplying sufficient artillery ammunition proved problematic until late in the siege. Eventually, the loss of the Armée de la Loire at the Second Battle of Orléans which was the defender's main hope of relief and the starvation of the civil population resulted in a ceasefire on 26 January 1871 and a surrender two days later.LePage 2006, p. 197