What transit restrictions were in place in Occupied Germany limiting military and civilian movement between the four occupation zones?

The period of early post-war occupation is paramount in characterising the politics in place there and then. It might be extended to characterised the restrictions in place by limiting the time frame to the time when exactly four different zones of occupation existed, as the British and American zones were 'unified' quite early (bi-zone) and then the French zone was joined as well (tri-zone).

Therefore the outer limits for this answer are the establishment of the bi-zone on January 1, 1947. Until that date all those zones were supposed to be "hermetically sealed". There should have been no uncontrolled movement of civilians at all. But of course there were movements. Undetected across zone borders or with a permit across the borders under supervision.

The biggest hindrance was crossing over the Soviet zone border, but the French made life particularly difficult for the other two Western allies. That is because the Soviets are painted as violating early the Potsdam agreement that they signed and the French as not really conforming to it – since they were absent from the negotiations in the first place. This lead to the French accepting some of those provisions and just ignoring others.

Those restrictions on movement were agreed upon as 11 Million soldiers and 14 Million refugees from the East as well as countless homeless people and displaced persons had to be controlled. But the Operations Overcast, Safehaven and Paperclip were also designed to hold German scientists and other qualified personnel either in place or freeing them for patriation into British or American service.

But those restrictions were not enforced immediately.

Erst auf massiven, auch wirtschaftlichen Druck der Amerikaner lenkte Frankreich schließlich ein. Am 22. Juni 1945 schlossen beide Siegermächte ein Abkommen über die Abgrenzung ihrer Zonen. Gut zwei Wochen später räumten die französischen Truppen die beiden Landeshauptstädte Karlsruhe und Stuttgart.

Schon am 19. September proklamierte General Eisenhower die Bildung des neuen Landes – zusammen mit Bayern und (Groß-)Hessen. Als Reaktion auf die frühen amerikanischen Ländergründungen schotteten die Franzosen ihre Zonengrenze ab. Auch für Privatpersonen waren fortan Passierscheine erforderlich. Nun begann auch die französische Besatzungsmacht – zögerlicher als die Amerikaner, aber gleichermaßen willkürlich und ohne Rücksicht auf historisch gewachsene Traditionen –, ihre Zone zu strukturieren.

(Karl Moersch & Reinhold Weber: "Die Zeit nach dem Krieg: Wiederaufbau in Südwestdeutschland", in: "Die Zeit nach dem Krieg: Städte im Wiederaufbau", Kohlhammer: Stuttgart, 2007, PDF: p16.)

Compare that treatment at the French zone border with that on the Soviet one, which got the Churchillian characteristics only on 30. June 1946. (Interzonal traffic.)

Those restrictions were sometimes quite peculiar. The following application for a permit argues that for buying one goat a permit should be given out, please:

Sourced from: Saar-Nostalgie, Dokumente, Urkunden, Ausweise, Formulare

Note the scraped off swastika on the stamp.

The above link shows quite a number of colourful examples, showcasing the chaotic parallelism of documents. That means: make it look official, and you got quite a chance for anything. Then, if you get caught with one of those not legitimate; some very tough luck may have been in store for the perpetrator…

While the aim was to issue to everyone a 'nobody moves' order, millions did travel and migrated. Cars, buses and trains were controlled tightly, other borders were practically green. The travel permits were eventually unified on June, 30 1946 with the inter-zone travel pass:

The French were therefore quite special in how they treated their occupation zone and the civilians there. Concerning the actual case, it has to be noted, that there was a bit back and forth regarding regulations:

The American counter-proposal was based on strictly logistical conceptions. The boundary between the French and American zones was to be drawn so as to leave in the American zone the main highway, or Autobahn, through Ulm-Stuttgart-Karlsruhe, aswell as the trunk railroad. Administrative and traditional divi sions were disregarded completely. The sole concern was to as sure access under American control to theMiddle Rhine and the seaports. On two occasions Mr. Winant and I wired strong protests to Washington against the breaking-up of both Baden and W?rttemberg. We pointed out that if it was the American intention to revive and strengthen the federal states in Germany as a possible safeguard against excessive centralization of power, it was hardly logical to begin the reconstruction of Germany by breaking up two of the L?nder possessing a strong sense of regional identity and a certain attachment to democratic self government. We suggested that some other device be sought for assuring freedom of movement over the highways and railways. Renewed instructions from Washington to insist on the War Department's proposal finally ended in the French acquiescing. The only concessions were the addition of Baden-Baden to the French zone and a provision for French access to Baden administrative records located at Karlsruhe, in addition to written French assurance that United States forces would enjoy freedom of passage across and above all parts of the French zone.

By early June 1945 these aspects of the determination of the French zone had been completed in the bilateral Franco-British and Franco-American negotiations. The Soviet representative had meanwhile been inquiring somewhat impatiently when the agreement would be ready to sign in the EAC. Now, however, a new problem, and a new source of delay, arose when the third Protocol on zones was put before the EAC. The American and British military authorities now insisted that the assignment of a sector to French occupation in Berlin required a partial readjustment of the sectors assigned earlier to the three other Powers.

Philip E. Mosely: "The Occupation of Germany: New Light on How the Zones Were Drawn", Foreign Affairs, Vol. 28, No. 4 (Jul., 1950), pp. 580-604.

We have to observe the distinction between freedom of movement and jurisdiction here. The Allies had an agreement that in theory should have allowed all of the military personnel freedom of movement throughout the occupation zones. However, moving Germans around was not part of that agreement, and *re-*moving Germans that were thought of "useful" was disliked by every Allied power.

In the case of Ambros the French found him apparently extremely useful for their purposes. The French had to be bribed to release him into American hands, and only accepted giving up Ambros after the Americans re-arrested Hermann Röchling, only to swap him with the French against Ambros. (Kim C. Priemel & Alexa Stiller: "NMT: Die Nürnberger Militärtribunale zwischen Geschichte, Gerechtigkeit und Rechtschöpfung", Hamburger Edition HIS, 28.05.2013, p475.)