Case Yelow starts
Fair weather came to stay in March 1940 (there was a fair weather turn in early February but no offensive was launched then). Germany invaded and seized both Holland and Belgium with few losses. As planned, French fighter did intercept Luftwaffe air attack in Belgium. Referred Allied air unit lost 3:2 vs German fighter which can be deemed as a not that bad outcome. Wehrmacht also attacked directly French army positions in Lorraine. There, a French garrison was heavily attacked and forced to make a forward retreating move but it survived the attack of the Germans that advanced into emptied location:
Later, in Allies turn, Canadians move a bit into Belgian territory north of Lille to reinforce the BEF position in case of a German attack on the city. French reinforced defensive positions by buying 2 garrison units deployed in Lille and Reims. In Lorraine, I was tempted to move French corps into Luxembourg this way cutting supply to advancing German corps but that would have left Allied unit without the shelter of the fortress hex. One of the benefits of placing a French corps in this fortress hex is that Germany is forced to leave a corps unit in the adjacent NE fortification hex. Otherwise, since now it's not possible to rail units directly to fortification hexes and adjacent German garrison cannot move because of ZOC, French would be able to advance into Germany owned hex, destroying the fortification. That might be the reason why adjacent xp German corps unit didn't advance into Luxembourg:
First turn of April 1940 (turn 12) saw the German reaching vicinities of Reims with a powerful leading armoured force. A total of 4 French garrison units were destroyed and another one was left battered. BEF Lille sector is being skipped by Wehrmacht for now, surely because of the needed regrouping of units coming from Holland:
Allies replied with their first counterattack in the campaign. German strong armoured push in Reims is directly threatening Allied front in their weakest sector, east of Paris. So Allies strongly reinforced with units referred sector and mounted a counterattack against northernmost PzKorps unit. Attack counted with air support and was rather successful achieving to halve in strength German armoured unit. Air combats were even since RAF fighter won 2:1 (the other step lost because of the ground attack on the PzKorps) and French Air force lost 1:2. French and British garrison units moved forward SE of Lille to cover the counterattaking action:
By late April (turn 13), German strong attacks all over the front between the coast and Reims much weakened good Allied defensive disposition achieved in last turn. Although in the center Reims was taken and British McNaughton mech was killed, the most visible progress was in northern France around Lille. 3 Allied garrison unis were destroyed there and Gort's unit in Lille was about to be left isolated. Another French garrison was attacked and ended battered in southern bank of Somme river:
Wehrmacht offensive in the coast left exposed approaches to Paris from the N-NW. Options for Allies were to retreat to the Somme, even leaving strongly entrenched Gort unit in Lille or to mount a counterattack with the aim to destroy or to leave badly damaged, the exposed German corps SE of Calais. With the French fighter in not much good conditions to provide air support (it was retreated 1 hex south), British carrier gave additional air cover. The fact is that air attacks on German inf were totally unsuccessful and they did not take any step from it, causing only a tiny lowering in morale. This poor air support probably much accounted for Allied units (French motorized corps, a French corps and Gort unit in Lille) not getting good results when attacking by land Axis inf unit that survived at 4 steps, that can be said it achieved a defensive victory (overall higher losses suffered on Allied attacking units). One of the French mechs moved to the Somme to reinforce Allied defense there whilst the central sector was again reinforced at the expenses of weakening positions in the east:
May 1940 (turn 14). Wehrmacht achieved a decisive victory in Lille destroying all Allied units north of the Somme. Calais and, of course, Lille were taken. Somme river line was completely reached. In the center, there was important German offensive operations and thus a PzKorps unit get adjacent to Paris hex destroying a French mech in the process. Germans mostly neglected Lorraine front:
In Allies reply, French army retreated to Seine river, move that maybe it should have done earlier. French air force unit retreated to Le Mans. Only Allied offensive actions came from RN BB's that made intense (and effective) shore bombardments of German units in Pas-de-Calais:
With the already recovered 3rd PzKorps unit coming from Belgium and all of Wehrmacht mobile units having the Seine river positions at range, German broke through French army defenses, killing 2 garrison, a corps and the other French mech. Many other French units ended battered. As a result of the operations, Paris was totally isolated from the rest of France:
This meant the end of any effective defense from the French. In Allied turn, only repairs to the reamaining units were made and even a garrison that was in the force pool, couldn't be deployed. French air force made a last sortie that was completely ineffective. RN ships mostly retreated and only a lonely BB shore bombed German corps 1 hex south of Calais.