"Fond" is not quite the proper word for the Rhenish relationship to Napoleon, which was quite complex and multifaceted. The Rhineland was of course a large and diverse polity prior to the French Revolutionary Wars and the reactions to the French were quite different in the left bank of the Rhine, and the right bank states of the Grand Duchy of Berg and the Grand Duchy of Baden, which had different political fates under Napoleon (left bank annexed, Berg in a personal union with the Bonaparte dynasty, and Baden being a client/satellite state). Local Rhenish elites often had to navigate the realities of French rule and institutions and the whole population had to contend with the consequences of French hegemony on the economy and conscription.

One important conditioning feature of the Rhenish reaction to Napoleon was that French hegemony in this region preceded the ascent of Napoleon. French Revolutionary armies occupied the region in 1792 and French rule had been cemented on the left bank by 1799. The experience of this pre-Napoleonic occupation provided a number of Rhinelanders a useful barometer to gauge the change of regime in Paris after Brumaire and the nature of later Napoleonic rule. There were a significant number of Rhenish Jacobins among intellectual circles in the 1790s that welcomed French armies as a force for order and progress. The young Joseph Görres, for example, exemplified the type of individuals that gravitated towards the French cause. Görres and other Rhenish Jacobins connected the French Revolution with the ideals of the Enlightenment and reform that percolated within the various clubs and political societies of the pre-Revolutionary Rhineland. These Jacobins found themselves the lieutenants of French rule, but soon found themselves politically sidelined by the largely military occupation of the region. More importantly, French Revolutionary army requisitions and indiscipline took much of the bloom off the Revolutionary rose for a number of Germans.

The Consulate and Empire offered a partial solution to the French excesses of the Revolutionary period. One of the hallmarks of the Napoleonic form of government was a systematic and streamlined form of administration. The chaos of the Revolutionary period soon gave way to a more stabilized form of French rule. The understaffed French state, there was always a discrepancy between Napoleon's ends and means, meant that the left bank areas often had to be staffed by local elites even though they were now part of France. In Berg, the Bonapartist rule was more paper than reality and Berg elites staffed the administration of the Grand Duchy. Likewise in Baden and Hesse, new men came to the fore in the state structures as one of the prices for being Napoleon's ally was to maintain larger military establishments.

Overall, a good many local elites found a role in the Napoleonic Rhineland, albeit under fairly complex circumstances. A number of older Jacobins rejected the monarchical turn of Napoleon, and a minority like Görres turned to a nationalistic rejection of the French. But most of the regions' elite found themselves cooperating with the new order. Older historiography stressed that French modern innovations were imposed from above, dragging the area into the nineteenth century and away from the ancien regime. However, much of the Rhenish elite of the pre-1800 period remained in place under Napoleon. Although new blood had entered into the power structure, much of the political power was distributed among the various corporate and social networks that characterized the pre-1789 Rhineland. Based on his own research into the region, the historian Michael Rowe aptly maintains that "the Rhineland was not 'colonized' by the French Empire; rather, Rhinelanders 'colonized' certain French institutions." Rhenish law in practice often amalgamated the Napoleonic code with older laws and traditions of the old Reich. Participation in the new state often meant an embrace of the culture and mores of Napoleonic rule, such as the militarization of administration and hierarchy. Such changes easily fit into preexisting late-Enlightenment discourses about the nature of power and the need for a structured society for progress.

But this "colonization" was not without its tensions. Napoleon's intended reform of the left bank's educational system to make it mirror his own reforms in France fell flat. The pre-1789 German university system was an important social node for German elites and Bildung retained an enormous cultural power. Napoleon favored higher education focused more on practical matters and both his lycées and polytechnic schools suffered from low enrollments. Rhenish elites might send their sons to the lycées, but would then send them to German universities in the interior, or as one Cleves patriarch put it, the Bonn lycée gave his son structure and order, but a German university exposed him to the humanistic German thought. The uniforms and martial character of French education meant that they became closely connected to the wider militarization of society and a form of de facto conscription.

Conscription was another stick in the craw for Napoleonic collaboration in the Rhineland. Napoleonic administration delegated the levies to local representatives and municipalities. Although there was constant pressure from the center to increase the numbers for Napoleon's wars, the delegation system was quite flawed. Local patronage networks, corruption, and connections rigged a system that already favored the upper- and middling- strata of society towards these groups. Substitutions of cash or replacement with another warm body to meet the conscription quotas was quite common in the Napoleonic Rhineland. Rhinelanders of modest means often formed syndicates for protection against the conscription lottery, pooling resources to buy a substitute if their lot came up. Paris and the local capitals repeatedly called for more order and less corruption, but these calls often went unheeded. Even though the Rhenish departments furnished a sizable amount of Napoleon's conscripts, the widespread culture of draft evasion, even among the beneficiaries of Napoleonic rule, calls into question the Empire's basic popularity.

Although resistance to conscription was something of a pan-European phenomenon, the Empire had another prominent strike against it: the economy. Napoleon's commitment to metallism as well as the need for domestic tranquility in metropolitan France straitjacketed French finances for the Empire's escalating costs of war. Although annexed to France, these non-French regions in the Rhineland, northern Italy, and the Low Countries were not immune to the Napoleonic practice of displacing the French defense burden on other countries. Indirect taxes increased significantly and often hit the poorer elements of society disproportionately. The taxation system of the Rhineland became more centralized and streamlined, and the Empire encouraged a larger cadastral project that would accurately convey a region's proper tax share.

Some sectors of the Rhineland economy and individuals did profit from French rule. The Roer department's industry grew when cut off from British competition and made steps towards industrialization of its textile industry. This hothouse growth allowed for some fortunes to be made and laid the basis for the region's post-1815 industry. Additionally, because Napoleon saw the region as a gateway into Central Europe, the French poured money into infrastructure and the development of roads. But the cumulative effect of this development was often inflationary and while some Rhenish entrepreneurs profited, there were a good many Rhinelanders left in the cold. Food prices tended to spiral and kept at higher levels despite decent harvests. The Continental System added a further stress on the region's economy, not only stimulating artificial that would collapse with competition, but exacerbating problems already existing with French rule. The case of the Berg is instructive here. Unlike the other Rheinbund states, Berg was geographically positioned where the Low Countries and Hanseatic ports were its main markets and suppliers. The closure of the Rhine and Hansa trade as well as French protectionism meant that Berg's economy collapsed. The situation was so dire that a delegation of Berg notables petitioned France in 1811 for Berg to be annexed by France to remove its customs barriers. Lobbying from French manufacturers, who also were hurt by the Continental System, prevented this petition from gaining traction with Napoleon.

The post-1815 legacy of French rule in the Rhineland was as contradictory as it was during the period of Napoleonic hegemony. When much of the region ended up under Prussian suzerainty at the Congress of Vienna, defense of Napoleonic institutions like the Code became quite normal in the Karlsbad Decrees. Part of this defense of Napoleonic norms and practices was generational; many of the young men of the 1820s and 30s had been socialized in the stable period of French rule and had only dim memories of the more exploitative 1790s. Napoleon had also entered into the pantheon of Romantic heroes despite his defeat (or perhaps because of it, as he got a tragic gloss from Waterloo and St. Helena) and there was a steady market for Napoleonic memorabilia both for domestic consumption and for sale in neighboring France, where its production was outlawed. But the defense against Prussian encroachments on Rhenish institutions was also a defense of local privileged against a "foreign" power. Just as embracing Paris's directives for a more centralized organization between 1799-1813 was a way to preserve local elite strength, defending Rhenish jurisprudence and administration methods meant retaining local elites in positions of power.

As a brief aside to kieslowskifan's excellent answer; it is worth mentioning that the Rhineland continued to have to have a complex relationship with France up until the inter-war period, when great efforts were made by the French government following WWI to support Rhenish separatism from the greater Kaiserreich (or Weimar at this point) during the Allied occupation of the Rhineland. Though there is dispute as to the extent to which the Rhinelanders really supported such a movement, the British in Cologne were very sceptical indeed (see David Williamson, The British in Germany, 1918-1930: The Reluctant Occupiers (Oxford, 1991)), it is an interesting thing to contemplate none the less, particularly as Cologne's mayor Konrad Adenauer would go on to have such an impact on the shaping of West Germany after the next war.

Good appraisals on the subject include: Epstein, Klaus, ‘Adenauer and Rhenish Separatism’, The Review of Politics 29, 4 (1967), pp. 536-545; McDougall, Walter, France’s Rhineland diplomacy, 1914-1924: The last bid for a balance of power in Europe (Guildford, 1978); Nadler, Harry E., Rhenish Separatist Movements during the Early Weimar Republic, 1918-1924 (New York, 1987).