Well, lets say Guderian ignores the "Stop"-order of 24th May.
He did similar later on in the East and such "ignoring" or not "receiving" such orders had some ... tradition (Gen. Francois at Stallupönen 1914 i.e.).
Therefore he reaches Dunkirk at the 25th (just 18 km away from his positions at the 24th of May AFAIK). What might force/motivate group Hoth as well as the "rest" of the 4th army to cross also the Yser and Aa rivers, cutting off fench 1st army even earlier. That leaves for the Brits as possible port of evacuation only Nieuport - at the moment.
Hitler might be upset, perhaps even furious of Guderians extra-tour, but ... success has merits and weight of its own and he might ceventually calm down due to this (as later as well with Guderians extra-tours).
With Belgium breaking away also Nieuport isn't available for the Brits anymore, the bag is closed around 28/29th May. Assuming Gort still manages to depart for Britain on Churchills order, the remaining BEF and french forces will likely surrender somewhere around 2nd/3rd June. Though there might still be some troops evacuated but I would assume well below 100.000 instead of 330.00 men.
-> MEGA-victory for Germany -> all disobeidience by Guderian forgiven atm (but maybe not forgotten ?)
Now, that the Brits doesn_t have much/anything to spare I would doubt, that the quick redeployments of the evacuted troop to France would occur ITTL, leaving the french almost completly by their own.
Churchill and the british cabinet would also NOT immediatly sue for peace or even an armistice at that point and try to convince France to "fight 'till the last frenchman", as they were already accused of IOTL. However, there also might now pop up an "invasion scare in Britain" with sooo few troops left. ... and eventually lead the cabinet - with or without Churchill - to ask for an armistice at least. But to come to this will take some time.
Maybe around the 7th/8th June, maybe via Mussolini, as he hasn't entered hostilities yet. Though I can think of him being rather reluctant to do so, seeing the german success. Hitler, "drunken" by this victory might be willing to accept such an armistice, but only for Britain, not for France, what might cause some further delays, as the british might quarrel, if they can/have to negotiate for their 'stubborn' ally, with whom they try to speak also for 'acceptable' terms for them.
What costs further time.
Case Red will still happen, maybe with a delay of 2 or 3 days (7th instead of 5th June), maybe with the same 'problems' 'Heeresgruppe B' encountered in the first days of their advance. But then only the technically attainable speed of Guderians and Rommels tanks will hinder them.
Seeing the french loosing the Brits might now accept an armistice only between them and germany, adandoning France. I could assume now an armistice between Britain and Germany alone around the 11/12/13th June.
Conditions :
- withdrawel of any british troops, that might still be in France - without their equipment
- unconditional "opening" of the Noth-Sea as well as the Channel for german ships
- opening of british over-sea harbours for german merchant ships ... and ofc giving any yet seized such ships back.
- repatriating of any german PoWs, that might be there, of british PoWs : the brits might get some, the wounded, the family fathers maybe, but the bulk will be spared for a peace settlement, what Hitler, now 'reinforced' in his believe in an anglo-german 'partnership' might believe to come quick and easily.
- cessation of any support to France, economical, financial and ofc militarily also (regarding material). The german 'wish' of receiving french troops, who might have made it to Britain or french naval units, that might have 'found' shelter in Britain might be fought off with the 'promise' of interning them, as would have (?) done a neutral state.
)Ofc for Britain it would be planned by the Brits only to serve as a breathing pause to rebuild, though Hilter might think/hope/dream of different.)
What IMO would cause Mussolini as the opportunist he was to immediatly start hostilities against France also, before any negotiations might come to a conclusion, maybe around 15/16th june. At that point I could assume the french also seeking an armistice - with Germany alone, but such a bid would be as futile as IOTL.
Therefore I could assume a "Compiegne" around the 20th June, some days earlier that OTL.
Though this "Compiegne" might look different. First because Hitler/Germany doesn't 'need' the french northern coast as a guard and staging point against Britain. Second because the french are now even more pissed off the Brits by abandoning them. They might even offer to 'fight' in a way against Britain, in the Mediterrainian i.e.. Though I would assume, that at least atm Hitler would refuse to have french fighting forces of importance left in metropolitan France.
- Eastern and north-eastern France might be occupied as OTL, as well as Britanny with its harbour for the KM and Bordeaux-region but NOT the long strip down the Atlantik-coast, NOT Normandy and Northern France, NOT Ile de France.
- French army in Metropolitan France (as IOTL) reduced to 100.000 men
- atm same as IOTL regarding french PoWs
- same regulations regarding german citizens in France (object to delivering to german authorities -> exilants)
- much reduced "occupational costs" (maybe 5 mil RM instead of 20 mil)
- BUT integration of french economy into the german/german controlled "autarky zone" or war economy (french industry producing for germany) already from the beginning
Mussolini will get as much or even fewer he gained OTL.
However, the german-british talks about a peace-treaty will be deliberatly delayed by the Brits until at least ...
Operation Catapult happens
(which IMO will happen, as the reasons for it would still stand and weight perhaps even more with the french-british alienation)
Though it would still be questionable if this would sober Hitler enough to forbabe the french, now furious about the Brits, to wage their on war against Britain (maybe in the colonies).
... open for further butterflies ...
