This was a Croat and German operation against the partisan forces of Josip Broz Tito in the region of Psunj and Papuk in Axis-occupied Yugoslavia in succession to 'Grün II' (20 March/8 April 1943).
Taking place about a fortnight later between 20 March and 8 April, though some fighting continued to 16 April, 'Braun' (iii) was a somewhat larger undertaking by some 35,000 men of Generalleutnant Josef Brauner von Haydringen’s 187th Reserve-Division and Croat elements intended to drive units of the 4th 'Croatia' Division (12th 'Slavonia' Division of the Yugoslav partisan army) away from the railway line linking Zagreb and Belgrade and also out of the Pozega valley.
The Axis forces were divided into five groups. The Grupa Sjever, known to the Germans as the Kampfgruppe 'Nord' and commanded by Podpukovnik Telarović, was to advance from Podravska Slatina to Kutjevo and Papuk with the 1/4th Regiment, 16th Ustase Battalion, 2/Syrmia Brigade, 4th Engineer Battalion and 4/Slavonia Brigade. The Grupa Jug (Kampfgruppe 'Süd') under Podpukovnik Vidaković was to advance from Slavonska Pozega to Kutjevo with the 2 and 3/4th Regiment, 1/5th Regiment, 2nd Assault Battalion, 2nd Rifle Battalion, German ES Battalion, 4th Engineer Battalion, 3rd Artillery Battery, and 13th Ustase Battalion with a howitzer platoon; the Grupa Zapad (Kampfgruppe 'West'), deployed between Daruvar, Pakrac, Okucani and Nova Gradiska, was to make concentric advances toward Papuk and Ravna Gora with Pukovnik Matija Čanić's 1st Mountain Division 'Ante Pavelić less its 1st Battalion and the 187th Reserve-Division less two battalions from Miokovice toward Voćin and Papuk, the 1/1st Mountain Division, parts of the 187th Reserve-Division and German 3rd ES Battalion; the Grupa Istok (Kampfgruppe 'Ost') was to advance from Brod na Savi (Slavonski Brod) to Kutjevo with Pukovnik Emile Radl’s 3rd Division less its 4th Regiment, 13th Ustase Battalion, and 4/6th Regiment; and Pukovnik Tomislav Bosnić's Slavonian Brigade with the 1, 2, 3 and 4/4th Regiment, 18th Ustase Battalion, one battery of the 5th Artillery Battalion from Slavnonska Pozega, and units of the 1st Mountain Division from Voćin and Pakrac.
Despite heavy fighting, the operation was unsuccessful. A report from the 187th Reserve-Division in May gave the German losses and confirmed that the Croat formations and units had suffered severe losses, and at the same time said that the partisan losses were not known but probably small, and the partisans' morale and organisation were excellent. It also agreed with the policy of retaliation on the civilian population by the Ustase, but also opined that its purpose was unclear as it was already known that such action only helped the partisan cause.
The Axis losses were 900 dead (18 German and 882 Croat), 1,100 wounded (67 German and 1,033 Croat), 1,250 Croats taken prisoners, and three Germans missing.
Between 20 March and 20 April, the 4th 'Croat' Division and III Operational Zone of Croatia lost 191 men killed, 309 wounded and 137 missing, together with 710 stricken by typhoid. The partisans also lost considerable quantities of matériel, though these were mostly small arms and more than counterbalanced by weapons captured from the Axis (mostly Croat) forces and including four guns and 25 mortars. The partisans also destroyed two armoured vehicles, five trucks, one factory, four railway stations, and seven trains.
On 16 April, immediately after official end of the operation, Croat forces made an effort to exploit the tactical situation and secure superiority in the Pozega valley, and attacked with the Slavonian Brigade. The partisans responded rapidly and effectively, surrounding the Slavonian Brigade and completely destroying it in less then three hours: some 900 Croat and Ustase troops were captured, together with Bosnić.
Although 'Braun' (iii) had been planned by the Germans, it seems that the Croat leader, Ante Pavelić, managed to persuade the Germans to let the Croat army run the operation in the expectation that victory would be easy in an area not far from Zagreb, the Croat capital, and some distance from the main partisan strength under Tito. Success would thus boost morale of both troops and civilian population still loyal to the puppet state of Croatia. It also seems that this was probably only operation in which German units came under Croat army control, and even the Kampfgruppen received Croat names.
The operation was effectively forgotten after the war, but it probably had a major effect on future events because of the Croats' high losses and their complete failure to inflict significant losses on the partisans. Instead of eliminating the partisan threat, 'Braun' (iii) actually increased it as the weapons that were captured allowed the creation of new partisan formations (10th 'Slavonia' Division and I Slavonian Corps) forcing the Germans and Croats to assign more troops to garrison duties and further fortify vital areas. A new operation was planned as 'Antun', but appears to have been cancelled as a result of the partisans' success.