They did for example let them move through Sweden into Northern Norway as far as I know.
What exactly did they do and how many German troops there were in Sweden for example?
Sweden did not allow German troops to move through Sweden to invade northern Norway.
Dietl's forces that invaded Narvik came aboard the 10 German destroyers that entered the fjord on the 9th of April.
Due to a very strong German pressure, Sweden decided to allow the Germans to evacuate their wounded and the militia (which were of questionable military value due to a lack of training and arms) raised from the crews of the sunken German destroyers and merchans vessels in Narvik over the Swedish railways. Sweden also allowed the Germans to send trains with food (enough for 4 000 men for 3 months), tobacco and medical supplies as well as medical staff to Narvik. The Germans forged red cross papers, and 191 of the 292 men sent through turned out to be German NCOs, machine gun specialists and recon soldiers, of which 41 arrived after the Allies had evacuated Narvik. The Germans put maximum pressure on the Swedes to allow transport of arms and ammunition to Narvik, which Sweden refused. The Germans offered to deliver 3 artillery pieces for each 2 that were allowed transit to Narvik (Sweden was at this time negotiating to buy more German 10,5 leFH18 howitzers). Germany suspended talks on the purchase of Bf 109 fighters and Ju 87 'Stuka' bombers and on the 16th of May 1940 demanded to be allowed to send three sealed trains that would not be inspected to Narvik. The German military attaché Bruno von Uthmann let it be known to his counterparts in the Swedish military that a refusal would be seen as 'an extremely unfriendly act', which was more or less a threat of war. The Swedish goverment sat in a crisis meeting on the evening of the 17th of May, which ended with the Prime Minister Per-Albin Hansson stating (my translation)
If we refuse, we will most likely be invaded an defeated, if we agree to a transit we will draw upon us the eternal enmity of Norway. I for one consider it better for a people to die with honour than live in dishonour. The German demands must be rejected.
On the 23rd of May 1940, the Germans tried to bribe the railway chief (with 30 000 SEK), the staiton master and customs officer (with 25 000 SEK each) to let a train through. A Swedish labourer earned about 10 SEK per day in 1940. The train was returned to Norway.
Sweden refused any transit of soldiers, weapons and ammunition to Norway as long as the war there was in progress. Not until after the Allies had evacuated the last of their troops on the 8th of June 1940 did this change.