The Seven Years' War was arguably the most important war in the history of the United States of America. After all, the revolt begun in the then-British colonies was a result of taxes levied there by Britain, which were intended to pay the debts Britain had incurred as a result of the War. If, for some reason, Britain lost the Seven Years' War, what would the immediate effects be on the American Revolution?
What would the effects of a French Seven Years' War victory be on the American Revolution?
The effect of a French victory would be rather subtle in the development of the Americas. The 13 colonies were compact and densely populated compared to New France, and vastly outnumbered the French colonists. Only lack of coordinated action and inability to "think outside the box" in military terms allowed the French to do so well in the initial phases of the "French and Indian Wars" (as the early part of the Seven Years War was known in the Americas), otherwise, you might expect the American colonials to simply roll over their opponents by sheer mass of numbers.
Metropolitan France, hard pressed with debts from the Seven Years War might not even look to New France, preferring to gain possessions in the Caribbean, India or other former British territories which have the potential to make money (the Caribbean was a locus of conflict due to the wealth to be extracted from the sugar trade, and even during the Napoleonic wars one of Britain's war aims was to protect the islands from French raids or invasion). New France, thinly settled and seen in the Metropole as a sinkhole of money and manpower ("quelques arpents de neige"), would probably be given some extra fleet resources to patrol the Atlantic seaboard, and rebuild the fortresses of Louisberg in Nova Scotia and the interior forts from Lake Champlain to protect the inland invasion route. The New French would have the 13 Colonies "surrounded" from the north and down the Mississippi Valley, and the Spanish would likely retain Florida. The Colonials would be subject to constant harassment and possibly demands to pay taxes or ransoms to continue to trade across the Atlantic.
The situation would be unstable, since the French have essentially sealed a pressure cooker. The Colonials, no longer under direct command of the Crown, and seeking revenge, protection from the contend harassment and (in the background) an outlet for their growing population, would be developing and refining wilderness warfare skills. People like Colonel Robert Rodgers would no longer be subordinate to British commanders used to fighting in linear formations totally inappropriate to the wilderness, and the Colonials would be building a force of Ranger companies to protect themselves and take the fight to the French. Colonial sea power would be in the form of small ships capable of blockade running and delivering raiding parties and hit and run attacks on French shipping from Nova Scotia to the West Indies.
The British, also seething from their defeat, would be quietly supporting the efforts of their colonials and working to create friction throughout the French Empire. The French, more concerned with their wealth generating colonies, will be less and less inclined to send support to New France when they have immediate threats on their own borders (like the Austrians) and need to keep money flowing into France from the Caribbean and India.
The setup for round two of the War is now complete. At the end of the 21 Years War (as future historians tend to call it), the French Empire faces financial ruin and their ability to continue the fight collapses. The 13 Colonies, having effectively been under self rule during this time, are accorded the status of sending representatives to Parliament. Their cause is helped by the strong internal economy and the ability to support the mother country with loans and investments. British finances are reorganized on this basis and sharp traders from New England become immensely wealthy buying into the East India Company, Hudson's Bay company and managing the former New France via the "St Lawrence Company" and the "Mississippi and Louisiana Company".
From this point, the contrafactuals are immensely different, leading to different North American boundaries, no French Revolution in the sense that we understand and a gradual separation of the Americas from England in the manner of Canada rather than an American Revolution.
The thirteen colonies would became part of French territory. Now depending on how well managed the new French regime was in handling their new English-speaking colonists. After all, the British manage to look after the Quebecois sufficiently well that they were happy not to join the American Revolution.
If the French made mess of managing the Americans well, the patriotic Americans would continue the fight on behalf of Britain. This scenario assume the Americans remain pro-British because they weren't levied taxes to help pay off the Seven Years War.
Perhaps the French do a good job of being the colonial overlords to the Americans. The Americans might behave somewhat like the Quebecois under the British.
France was also encumbered with massive sovereign debt in the aftermath of the Seven Years War. Finding measures to pay off their debt led to, wait for it, but I'm sure guessed it, The French Revolution!
The French Revolution could well provide the chance the American colonies have been waiting for. They rebel against La Belle France. With the aid and assistance of perfidous Albion. Now the American Revolution is allied with the British against France.
Assuming victory for the American-British Alliance, heads roll in France (literally) at their military failure. This assumes that, for example, Napoleon Bonaparte does not lead the French campaign against thirteen colonies and their British allies. Perhaps, if he did, his military career might lie in tatters on the other side of the Atlantic.
In the event of an American-British victory the thirteen colonies will rejoin the British empire. Possibly the misrule and onerous taxes and exercise that led the self-governing property owners to rebel in the first place won't happen. Parliament and the Monarchy will be different plus there will be a massive feel good factor from defeating the French.
North America will remain British. The French Revolution will follow a different course. There might be no Napoleon Bonaparte as Emperor of France. There is no reason for the British to colonize Australia. No war between the States in the mid-nineteenth century. The two World Wars in the twentieth century will be very different.