The teleprinter that received the messages from Hermann Goering is a post-war model, probably a Lorenz Lo2000, as it prints using a needle-matrix print head and uses both upper and lower case letters, which the 5-bit Baudot teleprinter code used at the time did not support.
A more accurate model of teleprinter would have been the Siemens T34 tape printer which was very common in both the Reichspost and the Wehrmacht teleprinter networks.
In the scene in the conference room a world map is visible in the background. On this map you can see China, Korea, and the Soviet Union all at their post-war borders something that would not appear in the bunker.
The soap dispensers in the bunker's restrooms were, despite their classic looks, not invented until 1950 in France. They are called "Savon rotatif" (rotary soap) and were - more or less a piece of soap on a wall-mounted stick - a standard issue in French schools and magisterial buildings for many years.
In the first scene featuring Heinrich Himmler, when chatting with Hermann Fegelein, the left ear piercing of actor Thomas Kretschmann can clearly be observed. While not unheard of at this point in history, it is a near impossibility that Fegelein would have such a piercing.
The last day of the war, Weidling's speech to the German soldiers is transmitted via car with loud speakers. This car is actually a Soviet car GAZ-63 and its production has begun 3 years later - in 1948. There's Russian text visible on the hood of the car: "Avtozavod imeni Molotova" - Molotov's car factory.
(at around 40 mins) Immediately when Chapter 7 begins, there are two armored troop-carrier SdKfz251 on the background. They are actually Czech OT-810 and their production has begun 13 years later - in 1958.
Axmann was an Reichsjugendführer, and his collars should have had three golden Oak leaves in the center surrounded by large laurel wreaths on red fabric. In the film it is a Gauleiter (NSDAP), and it is unlikely that he was actually a member of the Nazi party, as the collar that he wore only had golden leaves, and that insignia was used before 1939. After 1939, the Third Reich Eagle in gold was added on the collar, therefore he was wearing an outdated uniform. It's possibly that the prop designers could not find golden colored Reichsjugendführer collars, and instead decided to use Gauleiter ones. His hat is also completely wrong, it would have been similar to the one used by Dr. Joseph Goebbels.
When Hermann Göring's telegram is received in the bunker, a closeup shows the teletype machine printing the message in lowercase letters with German umlauts converted to ae, oe, ue and the closing note "heil hitler, h. goering, reichsfeldmarschall" aligned to the left. When the communication officer removes the paper from the machine, the text is mixed uppercase/lowercase with umlauts and the closing note is right aligned.
After Magda Goebbels poisons her children, she comes out of their room and immediately crouches against the doorframe. In the next shot she's considerably further away from the doorframe than in the previous shot, with no time to have moved.
General Karl Koller can be seen in the first shot of Hitler's first strategy conference. However in the next shot of all the generals (after Adolf Hitler orders to have Walther Wenck attack with the 12th Army) he has disappeared. In a deleted scene, Hitler ordered Koller to mobilize the remaining air force to support Steiner's attack and Koller left. This exchange occurred prior to Joseph Goebbels's opening line.
During the flight from the bunker, Müller (Schenck's adjutant) is shot. When the camera cuts to his body on the ground there is a bullet wound in his right cheek. But no wound is seen on his face in the previous frames as we hear the shot and see him falling.
When SS-Obersturmbannführer Schenke wants to speak to the fat SS-Obergruppenführer about breaking apart his administration, on the yard of the supply department, at the first shots, SS-Obergruppenführer's foreface is intact; at the sudden, at the next shot, there is a small bandage at SS-Obergruppenführer's foreface.
About 17th minute of the movie. A one-armed war veteran has found his son Peter Kranz near an air defense gun on the street of Berlin. It's supposed to be a German 8,8-cm-Flugabwehrkanone (88 FLAK) - these cannons have been often used as anti-tank guns. But in the movie shown is a Soviet air defense gun 52-K (caliber of 85 mm). This part of movie has been made in St.Peterburg in Russia.
In the film, Hermann Fegelein is shown as being arrested, dragged outside and summarily shot. In fact, Fegelein was arrested and kept in a cell for at least three days in the Führerbunker before Hitler ordered him stripped of rank and to be subjected to court martial, during which he was so drunk he vomited and urinated on the floor. It was only after the court martial that he was shot.
After Adolf Hitler's conference on 22 April, when it was announced that Steiner's assault did not happen, Hitler and his entourage exited to the corridor where all kinds of people were waiting. Amongst them a Großadmiral (the equivalent of a 5-Star or Grand Admiral). The only two Grand Admirals during the Third Reich were Eric Raeder, who had resigned from his command post earlier and was not in the Führerbunker during the last days, and Karl Dönitz, who had his headquarters in Flensburg in Northern Germany, far away from Berlin.
According to Traudl Junge's memoirs and several other sources, Magda Goebbels was not present when Adolf Hitler said his goodbyes before committing suicide. She had locked herself in her room at the time.
Toward the end of the film when SS Doctors Ernst-Günter Schenck and Werner Haase are walking through the bunker on their way to see Adolf Hitler, an SS officer is seen wearing a Wehrmacht Officers hat.
In his memoirs, Albert Speer stated that when he went to say goodbye to Magda Goebbels he could barely get more than a few words out, as Joseph Goebbels was in the room with them. This renders the lengthy conversation between them factually inaccurate.
Götz Otto is credited with portraying SS Hauptsturmführer Otto Günsche, when in reality Günsche was a SS Sturmbannführer. Wardrobe got it right however as his uniform has the correct collar and shoulder insignia.
Adolf Hitler is going to award the young soldiers with an Iron Cross in a Reich Chancellery garden, just behind the bunker's entrance. There is the two storey Reich Chancellery building visible behind the bunker and a ventilation shaft. But actually this part of Chancellery was one storey building with round windows in the attic.
Thomas Kretschmann portrayed SS Gruppenführer Hermann Fegelein, but his collar insignia is that of an SS Brigadeführer.
Fegelein attained the rank of SS Obergruppenführer before being executed. His collar insignia should have a diamond below the leaves
During the "farewell" scene, Adolf Hitler gives Magda Goebbels his golden NSDAP badge. He attaches it to her dress as if the badge has a spring pin lock. These badges, however, had a nut-and-bolt type of locks, not spring pins. Therefore, the procedure could have not been as easy as it was shown: he would have made a hole in her dress first, attached the badge and then fixed it with a nut cap from the inner side.
In the scene where SS officer Fegelein is executed for treason and desertion, no bullet wounds or blood appear on his uniform when the machine pistol's bullets hit him. Also, the weapon does not eject any empty cartridge cases while it is being fired.
Immediately when Chapter 7/Fall of the Third Reich begins, there are two German soldiers driving a motorcycle with side car. On the right side is a fresh pile of dirt that is covering an explosive underground, supposedly to look like an artillery shell instead.