It's a large task to carry out a thorough comparison between these two kingdoms during the period in question, but a few main points stand out and can be dealt with concisely. France had been an established kingdom since the Middle Ages, but Prussia's status as a kingdom began only in the eighteenth-century. Territorial acquisitions under Frederick the Great, who reigned from 1740 to 1786, made Prussia a major European power for the first time. The Prussians seized Silesia from Austria and also acquired Polish territory in a series of "partitions" of Poland, in which Russia and Austria participated with Prussia. At the same time, Frederick was important as a (relatively) liberal monarch in the Enlightenment period and as a patron of the arts. He was a friend of Voltaire, was a musician himself, and employed J.S. Bach's son Carl Philip Emanuel as court composer. In a celebrated visit to Frederick's court, the elder Bach performed for him and was enthusiastically applauded by Frederick.
By contrast, France was somewhat on the decline during the same period, unable to gain territory in the War of the Austrian Succession (1740-48) and losing badly in the Seven Years' War (1756-63). By the terms of the Treaty of Paris in 1763, the French were expelled from power in North America. The British took over Canada, while Louisiana (which included the huge swath of territory west of the Mississippi River that later became the Louisiana Purchase) was ceded to Spain. At this point, Britain, France's long-time enemy, had clearly become a greater power than France. The French achieved partial revenge by supporting the Americans in the War of Independence, but failed in their attempt to take over British and Spanish territory in the West Indies. The cost of the war also drove France massively into debt and was one of the factors leading to the French Revolution and the overthrow of the Bourbon monarchy in 1792. In that year, Austria and Prussia declared war on Revolutionary France. Ultimately, the Prussians were losers in the attempt by the monarchies to defeat France and perpetuate the old order of Europe . With Napoleon's invasion of Germany, Prussia was defeated and turned into a client state of France. It was not until 1815, when Prussia cooperated with Britain and its allies in the final defeat of Napoleon at Waterloo, that Prussia's rise as a power continued. Prussia eventually became the most important of all the German states and led the unification of Germany later in the nineteenth-century.