From
A war to be won, history of the second World War, by Alan Millett; Harvard University Press, 2000
…In the Netherlands, the dutch army refused to cooperate with the allies, and despite initial success defeating the german airborne troops, by May 14 the germans had occupied half of the country.
…The dutch army surrendered after the bombing of Rotterdam. The german invasion was too fast and the germans fastly achieved air superiority over this sector, and the French plans to resist at the Breda line quickly failed, allowing the germans to advance towards Zeeland and outflank the allied defense around the Dijle.
…The battle of Gembloux Gap was the largest battle between armoured formations the world had ever seen. It started in May 15 when the germans, after failing at surprising the allied armies in Sedan, managed to cross the Meuse in three points between Dinant and Liege. By this moment, what was intended to be a swift and decisive battle to envelope and destroy the bulk of the allied army was slowly becoming precisely what the germans had tried to avoid: a positional battle in which only luck or the sheer force of numbers would decide the outcome.
…Gamelin had repetedly pointed out that resisting at the Dijle was too risky in terms of entrenching and supplying, and would have preferred to keep the allied forces west of Brussels. It was political pressure to protect the Belgian capital which forced him to choose the Dijle river for his defense line. When the Netherlands surrendered in May 15, his north flank became exposed, and the risk of a german advance towards Antwerp that would envelope the allied army became very real.
…It was superior tactics and training who decided the outcome of Gembloux, although at a very high cost for the Wehrmacht. The allied armour doctrine was still very inferior to its german counterparts, and the lack of radios in the allied tanks became a serious issue. Despite the superior firepower and armour of the French B1’s, soon german forces under the command of generals Rommel and Hoepner would advance towards Brussels, threatening the entire allied position. The constant german attacks through the Ardennes between Sedan and Dinant, although fruitless, were also successful tying a lot of French armoured forces far away from the decisive battle.
…By may 20, the germans had finished reorganizing in the dutch sector and were preparing to attack towards Antwerp. The allied High Command, with generals Gamelin, Gort, Miaja and King Leopold of Belgium, decided to withdraw from the Dijle line towards Gent, despite Leopold’s staunch opposition.
From
The Second World War, by Winston Churchill, 1951
..Our greatest fear during late May was that our withdrawal from the Dijle could turn into a disordinate mess that would allow the germans to destroy the allies in Belgium. Fortunately for us, two weeks of endless battle had strained the germans more than us, and the allied forces were able to withdraw in order.
…I feel sorry for King Leopold. Belgium had been the first country to see the painting in the wall and had prepared his armed forces for a german invasion ever since 1935, and the astounding performance of the Belgian forces, specially their antitank artillery, cannot be overstated in any tale of the Battle of Belgium. It is understandable that he opposed vehemently that the allied army withdrew west of Brussels; but there was no other option. Gort’s Expeditionary Force was under very heavy pressure in Antwerp, and Rommel was breaking through at Gembloux. If his panzers reached Charleroi, the allied expeditionary force would be destroyed.
…Only in the southern sector of the front between Dinant and Malmedy, the germans were unable to progress. The staunch resistance of the French army and the Spanish expeditionary force prevented them from crossing the Meuse, and their diversion movement[1] through the Ardennes failed to surprise our forces.
[1]Yes, the Ardennes offensive is considered as only a diversion attack in TTL.
From
Erwin Rommel’s diaries
May 26, 1940, near Gembloux, Belgium
…Little combat today. The enemy is withdrawing towards Brussels after inflicting us serious losses. Five panzers reported lost today in combat against British Matildas. Heavy air combat over our positions. Despite being in a position to achieve a decisive breakthrough, my panzers are running out of fuel and ammunition.
May 27 1940, near Gembloux, Belgium
…The enemy is escaping while my Panzers are sitting idle here. Getting fuel and ammunition is now our primary concern, but it seems that the supply lines are in total chaos due to enemy air attacks. Little advance today; my men are scavenging supplies as they can from abandoned Belgian depots. We’re losing a decisive opportunity here.
June 1 1940, near Charleroi, Belgium
…Radio reports that our avant-garde is at the outskirts of Brussels after crossing the Dijle line. The Belgian government has fled to Ostend. My panzers have finally reached their objective, only to find that the enemy has withdrawn towards the French border. If only we had had a little more fuel one week ago! Enemy attempts to cross the Sambre river rejected. My division has lost more than one hundred panzers in 20 days. I doubt we can attempt to invade France without stopping and losing our momentum.
June 4 1940, between Charleroi and Mons, Belgium[1]
…British Matildas counterattack my avant-garde. My division has suffered heavy losses. Continuing our advance would be risky and useless. Radio reports inform that Von Reichenau has crossed the Scheldt and is nearing Ghent.
[1]The day the Dunkirk evacuation ended in OTL.
From
A war to be won, history of the second World War, by Alan Millett; Harvard University Press, 2000
…By June 10, the germans had won the battle of Belgium, but it had been a pyrrhic victory. The panzer divisions and the Luftwaffe had suffered staggering losses, the British and Spanish expeditionary forces were still standing, and despite its huge casualties, the French army had been able to withdraw towards the French border. However, the allies had lost almost all their armoured reserves in the great battle of the Gembloux Gap, where the german tactical superiority defeated the allies’ numbers and superior firepower.
…After one month of endless and vicious fighting, the situation stabilized for a few weeks while both sides stopped to reorganize their armies. In Paris, the French government thought that the worst had passed as the german onslaught seemed to have been stopped. In Berlin, Hitler congratulated that the wehrmacht had been able to accomplish most of their objectives in only a month, although the huge losses and the fact that the Belgian coast was still in allied hands were a great disappointment. Only a man, Erich von Manstein, thought that the campaign had been a complete failure, and that it would soon turn into a trench hell like in the last war. During June and July 1940, his lobbying would finally convince Hitler that the French had to be decisively defeated before Germany could turn east.
This map (shamelessly stolen from wiki's excellent and detailed article on the Battle of France) represents the front situation around June 5. Note that the grey area are the german advances in OTL
between May 16 and 21. The germans are happy they have accomplished most of their objectives and mauled the allied armoured forces, but they cannot even suspect what could have happened if their advance through the Ardennes had succeeded: