The Constitution of the Duchy of Warsaw may be regarded as the model implementation of the Napoleonic constitutional ideas. The Constitution contained the quintessence of Bonapartism: personal rule of the monarch based upon the professional centralized bureaucracy, accompanied by parliament whose role was more decorative than real. Although such system was alien to Polish parliamentary tradition the Poles surprisingly easily adapted themselves to it. Many factors were at work to reach that goal: longing for independent state, the desire to do away with the harsh Prussian regime and the hopes of full restoring of independence. What was of utmost significance was the fact that state apparatus became the fully national structure. The Duchy of Warsaw was acknowledged as the constitutional continuation of old-time Poland.

The Napoleonic civil law legislation, as introduced in the Duchy of Warsaw, was anti-feudal in its content. Hence, it sometimes did not fit the socio-economic circumstances prevalent on the Polish soil. Yet, despite the fact that the Code Civil had no stronger links with the Polish legal tradition and contained the provisions which were excessively revolutionary from the point of view of conservative attitudes of landed gentry, it soon ceased to give rise to negative emotions. This was so because its liberal and egalitarian assumptions in fact corresponded the freedom-promoting ethos of Polish nobility. The ardent supporters of the Code were not only detectable among the governing elites but, one might say, the entire society promptly adapted themselves to its provisions. However these norms of the Code Civil which dramatically departed from Polish mentality, like e.g. lay matrimonial law, remained a dead letter. The Napoleonic legislation did not, therefore, thoroughly transformed the social relationships on the Polish soil but it undoubtedly had an impact on the democratization of Polish society and modernization of state structures, particularly the administration and the judiciary.