The story I heard is that revolutionaries thought that judges were corrupt and thus should be left to interpret the law, and thus should closely follow codified rules. Is that historically accurate?
France invented the civil law system and adopted it in connection with the French Revolution. Napoleon commissioned it in 1804.
The summary of the story is here. As Wikipedia explains:
Before the Napoleonic Code, France did not have a single set of laws; law consisted mainly of local customs, which had sometimes been officially compiled in "custumals" (coutumes), notably the Custom of Paris. There were also exemptions, privileges, and special charters granted by the kings or other feudal lords. During the Revolution, the last vestiges of feudalism were abolished.
Specifically, as to civil law, the many different bodies of law used in different parts of France were to be replaced by a single legal code. The Constituent Assembly, on 5 October 1790, voted for a codification of the laws of France, the Constitution of 1791 promised one, and the National Assembly adopted a unanimous resolution on 4 September 1791, providing that “there shall be a code of civil laws common for the entire realm.” However, it was the National Convention in 1793 which established a special commission headed by Jean-Jacques Régis de Cambacérès to oversee the drafting process. His drafts of 1793 (for which he had been given a one-month deadline), 1794, and 1796 were all rejected by a National Convention and Directory more concerned with the turmoil resulting from the various wars and strife with other European powers. The first contained 719 articles and was very revolutionary, but was rejected for being too technical and criticized for not being radical or philosophical enough. The second, with only 297 articles, was rejected for being too brief and was criticized for being a mere manual of morals. The third, expanded to 1,104 articles, was presented under the Directory, a conservative regime, but never even came up for discussion.
Another commission, established in 1799, presented that December a fourth scheme drafted in part by Jean-Ignace Jacqueminot (1754–1813). Jacqueminot's draft, the so-called loi Jacqueminot, dealt almost exclusively with persons and emphasized the need to reform the Revolutionary divorce laws, to strengthen parental authority and increase the testator's freedom to dispose of the free portion of his estate. It was, of course, rejected.
Napoleon set out to reform the French legal system in accordance with the ideas of the French Revolution, because the old feudal and royal laws seemed confusing and contradictory. After multiple rejected drafts by other commissions, a fresh start was made after Napoleon came to power in 1799. A commission of four eminent jurists was appointed in 1800, including Louis-Joseph Fauré and chaired by Cambacérès (now Second Consul), and sometimes by the First Consul, Napoleon himself. The Code was complete by 1801, after intensive scrutiny by the Council of State, but was not published until 21 March 1804. It was promulgated as the "Civil Code of the French" (Code civil des Français), but was renamed "the Napoleonic Code" (Code Napoléon) from 1807 to 1815, and once again after the Second French Empire.
The process developed mainly out of the various customs, but was inspired by Justinian's sixth-century codification of Roman law, the Corpus Iuris Civilis and, within that, Justinian's Code (Codex). The Napoleonic Code, however, differed from Justinian's in important ways: it incorporated all kinds of earlier rules, not only legislation; it was not a collection of edited extracts, but a comprehensive rewrite; its structure was much more rational; it had no religious content, and it was written in the vernacular.
The development of the Napoleonic Code was a fundamental change in the nature of the civil law system, making laws clearer and more accessible. It also superseded the former conflict between royal legislative power and, particularly in the final years before the Revolution, protests by judges representing views and privileges of the social classes to which they belonged. Such conflict led the Revolutionaries to take a negative view of judges making law.
This is reflected in the Napoleonic Code provision prohibiting judges from deciding a case by way of introducing a general rule (Article 5), since the creation of general rules is an exercise of legislative and not of judicial power. In theory, there is thus no case law in France. However, the courts still had to fill in the gaps in the laws and regulations and, indeed, were prohibited from refusing to do so (Article 4). Moreover, both the code and legislation have required judicial interpretation. Thus a vast body of case law has come into existence. There is no rule of stare decisis