1898
The problem with an Anglo-French war over Fashoda is that it requires the French to be very, very stupid. Because:
a) the British navy was much stronger than the French, and
b) France's main ally, Russia, had made it clear they would not fight Britain over France's African ambitions.
The Russo-French alliance was directed at Germany.
Hence if France goes to war over Fashoda it would have to be in a fit of nationalist hysteria.
Results:
1: naval war. French commerce raiders do some damage before being hunted down. French fleet is either destroyed or blockaded in port.
2: colonial war. The British, with command of the ocean, isolate the French colonies and pick them off one by one. (A replay of the later stages of the 7 Years War).
Algeria might be a real problem; it had a substantial garrison and many French settlers, including many reservists. OTOH the native population was anti-French and the French element was concentrated in coastal cities vulnerable to the guns of British battleships.
Conclusion: French lose bigtime. Salisbury's government takes some French colonies -- reluctantly, and forced into it by public opinion. Certainly some West African territories; possibly Madagascar and some SE Asian real estate. Possibly basing rights in Algeria, and a clause forbidding the French to maintain naval units in N. Africa.
Conversely, depending on political developments in Britain, they might take the lot, but that's low-probability.
Oh, and the Second Boer War gets delayed; Salisbury won't back any demarche by Milner with bigger fish to fry first. OTOH the Boers may back down when Britain beats the French, thus showing that nobody could help them.
Longer term, this of course upsets the Entente Cordial; it would probably take the French a fair length of time to stop resenting perfidious Albion, and for that matter the Russians for not supporting them.
So if there's a WWI analogue, the British stay neutral and the French are defeated.