The Civil Code of Napoleon was one of the chief legacies of the First Empire in the wake of of his defeat. The rolled-up Code features prominently in David's famous 1812 portrait The Emperor Napoleon in His Study at the Tuileries that showed an Emperor hard at work well into the night. The great man himself would allegedly say of the Code on St. Helena:

My true glory is not to have won forty battles, Waterloo will wipe out the memory of so many victories. However, nothing will erase my Civil Code that will live eternally.

Although Napoleon's stock had lowered quite a bit by 1814, many of the states liberated from French rule and France itself retained the Code Napoleon had created and in many cases, imposed. The retention of this legacy of Napoleon stemmed from several reasons, the most important of which was that the Code was useful to the various restoration states.

It is important to remember that the Bourbon restoration was not fait accompli achieved by Napoleon's military defeat. The Allied leadership had very little in the way of concrete plans for a post-Napoleon French government when they invaded France. Metternich expected either to deal with a Bonaparte regency or a chastened Napoleon after Allied victory and Tsar Alexander I toyed around with granting clemency to Napoleon but giving the French throne to some other Bonapartist figure. The Swedish regent Karl Johan (formerly known as Marshal Jean Bernadotte) likewise angled to replace Napoleon, although few in the Allied camp took him seriously. The Bourbons were somewhat out the loop when it came to these maneuverings. But the fortunes of the old ruling house were restored by a Napoleonic institution, the Senate. Talleyrand may have been disgraced, but he was still a Senator and he sounded out like-minded Senators in his salon to legally depose Napoleon. While there was some thought of a regency for Napoleon II, Talleyrand felt that such an arrangement would be a back-door for his father. Thus when the Senate legally deposed Napoleon for violations of the constitution, they invited Louis XVIII back to the throne as a semi-constitutional monarch under the auspices of the 1814 Chartre.

The fact that Louis XVIII came to power at the behest of various elites disaffected by Napoleon's rule explains some of why the Civil Code remained intact. The Senators and other Napoleonic elites were some of the winners of the Revolution and wanted to be certain that these gains of the Revolution remained intact. The Code allowed for protections of private property and a stable order. Had Louis XVIII turned to Bourbon despotism, the Code would likewise provide further protection for these elites in case the relatively weak Chartre failed to restrain the Bourbons.

But the Code's utility was not just limited to the Napoleonic elite. For all of the claims that the Bourbons "forgot nothing and learned nothing," was not quite accurate as far as the Code was concerned. Louis XVIII and his ministers recognized that turning back the clock to a pre-1789 world was impossible and there had to be some accommodation given to the France Napoleon's rule had created. Pushing against the Code would have weakened the fragile alliances that had enabled the Restoration in the first place and given more grist to the mill for Bonapartists seeking a return of the Bonaparte dynasty to France.

Yet it was not just domestic Realpolitik that ensured that Louis XVIII retained much of Napoleon's legal system. For all of Napoleon's claims that the Code was an instrument of enlightenment, it was also a somewhat authoritarian set of legal principles that could be quite socially conservative. While the Code guaranteed equality before the law, the Penal Code of 1810 had provisions for arrest without trial and granted significant powers to state prosecution. The Civil Code's provisions on family law sanctified the role of the pater familias, restricted the role of women in civil society, and upheld a very patriarchal system, as Stanley Kowalski was fond of reminding his wife and sister-in law. Article 291 of the penal code greatly limited private organizations by declaring that any association of over twenty people that deals with "religious, literary, political, or other aims," had to have official sanction from the government in order to legally meet. In an era of secret societies and real conspiracies against the government, it is no surprise that Article 291 survived various regime changes in France until 1901. The Civil Code strengthened the rule of law and the sanctity of private property, but it along with Napoleon's other legal codes strengthened the state's power and authority.

Étatist utility was one of the reasons why the Code or variations of it remained in some areas formerly under French rule. The various Codes usually had to make some allowances or changes to make it politically suitable. The Kingdom of Poland, which was nominally an independent state under rule of the Romanovs, modified the Code's provisions on civil marriage and other areas of interest to society. The various Italian states had a more circuitous return to the Code as a number of Restoration governments had a knee-jerk reaction against the Code. But the Code's provisions for an ordered, legal society were quite useful for the monarchs of these states. The Code's fate in the German states was more tangled than in Italy. A number of German elites, especially within the Rhineland, had colonized the legal apparatus under French dominion. The defense of the Code became a defense of both local privilege as well as local rule. The Hohenzollerns in the Rhineland presented an interesting contrast to the Bourbons. While the Prussian state did not feel the need for the Code, the Prussian civil code presaged some of the more authoritarian aspects of the Napoleonic Code, they accepted the use of the French legal system in the Rhineland. But unlike the Bourbons, the Hohenzollerns were not especially at ease with this "French" legal system and fights between the Rhennish elites and the Prussian state over legal jurisdiction punctuated the Vormärz period between 1815 and 1848.

Pace Napoleon's claims on St. Helena, the Code did not survive his downfall unscathed. None of the post-Napoleonic legal systems kept the Code in its original, unadulterated form. There were various sundry issues that were modified or reversed even if the general principles of the Code survived. The survival of the Code was in no small measure because the Code fit the political circumstances of post-1815 Europe far better than its pre-Napoleonic predecessors. Starting a new legal code from scratch in 1815 would have been time-consuming and unnecessary given the Code did not fundamentally undermine Restoration rule. In many cases, the state-strengthening and socially-conservative aspects of the Code were an incentive for restored monarchs to retain Napoleon's legal legacy.

Sources

Laven, David, and Lucy Riall. Napoleon's Legacy: Problems of Government in Restoration Europe. Oxford [u.a.]: Berg, 2000.

Price, Munro. Napoleon: The End of Glory. Oxford: Oxford University Press, 2016.

Rowe, Michael. From Reich to State: The Rhineland in the Revolutionary Age, 1780-1830. Cambridge: Cambridge University Press, 2007.