Many of the philosophes cited as inspirations by the liberal revolutionaries (though not, admittedly, the radicals) were strongly impressed by the English constitution, which they believed to be the best in existence. Voltaire, in particular, wrote at length about Great Britain, and described its government as a "happy mixture" that combined monarchy, popular government, and aristocracy in a way that best preserved the liberty of the people. Montesquieu also admired the English government for similar reasons. There was, in short, a strong Anglophilic tradition among French liberals that was not necessarily filtered through the American experience. I agree that the American Revolution was inspirational to many in France, but many of the ideas that lay behind their critique of the ancien regime predated events in America by decades.
It is also a bit simplistic to say that "the British" had "nothing but disdain" for the French revolutionaries. Instead, the outbreak of revolution in France excited reformers in Great Britain, who hoped that the event might lead to further reform in their country. The Revolution, in other words, was understood in the context of political struggles within England itself, just as it was in the United States. Edmund Burke's Reflections on the Revolution in France was written as a refutation of one of these reformers, Richard Price, who sought to associate the principles of the French revolutionaries with those of the Glorious Revolution of a little more than a century earlier. Burke's work is noteworthy due to its own brilliance and that of the radicals who responded to it, but the debate also took place within Parliament, where Burke skirmished with former political allies, notably George Fox, who supported the revolution in France. Burke's disdain for the French Revolution in no way represented a consensus of opinion.
Actually, the statement is incorrect. The French were NOT inspired by the British system; in fact the British were the enemy of the French; therefore they had nothing but disdain for them. Any inspiration from the British was in fact indirect--by way of the Americans.
The French were, in fact inspired by the American Revolution which had been romanticized by French thinkers. The French government had contributed financially to the American Revolution, which they saw as the embodiment of the right of the people to overthrow a tyrannical government. The language of the Declaration of the Rights of Man were strikingly similar to that of the American Declaration of Independence:
The representatives of the French people, organized as a National Assembly, believing that the ignorance, neglect, or contempt of the rights of man are the sole cause of public calamities and of the corruption of governments, have determined to set forth in a solemn declaration the natural, unalienable, and sacred rights of man, in order that this declaration, being constantly before all the members of the Social body, shall remind them continually of their rights and duties; in order that the acts of the legislative power, as well as those of the executive power, may be compared at any moment with the objects and purposes of all political institutions and may thus be more respected, and, lastly, in order that the grievances of the citizens, based hereafter upon simple and incontestable principles, shall tend to the maintenance of the constitution and redound to the happiness of all.
- Men are born and remain free and equal in rights. Social distinctions may be founded only upon the general good.
- The aim of all political association is the preservation of the natural and imprescriptible rights of man. These rights are liberty, property, security, and resistance to oppression.
- The principle of all sovereignty resides essentially in the nation. No body nor individual may exercise any authority which does not proceed directly from the nation.
The Declaration had in fact been originally drafted by the Marquis de Lafayette after conversations with Thomas Jefferson who was then the American envoy to France. Jefferson, of course, was no great friend of the British, but had himself been inspired by John Locke, the British philosopher. Lafayette had great respect for George Washington, whom he saw as a father figure. So, any British influence was by way of American ideas.
The English political system is not generally mentioned as an inspiration for the French Revolution. However, if you must make this argument, you can point to the fact that the English system was much more democratic than the French system was. The English system had a powerful Parliament in which even the commons had a major role. The church did not play as great a role in English government as it did in French government. The earliest of the French revolutionaries, then, could have looked to England as an example of a system that was a monarchy but which also was fairly democratic.