'Justine' was a US special forces operation to parachute an Office of Strategic Services operational group into the Vassieux area of German-occupied France to aid the local resistance forces (28 June/24 August 1944).

The object of the undertaking, which was the second of the series, after 'Emily', to be undertaken in France from the OSS base in French Algeria, to strengthen the resistance forces in the Vercors region and to carry out guerrilla warfare against the German supply lines, lines of communication and telecommunications in this region.

Commanded by 1^st Lieutenant V. G. Hoppers with 1^st Lieutenant C. L. Myers as his second-in-command, the 15-man operational group departed Blida at 21.30 on 28 June, and the aeroplane reached the 'Taille Crayon' drop zone near Vassieux at 00.10 on 29 June. The DZ was excellent for the arrival of the personnel and all their equipment and supplies, and the resistance reception was well organised despite the fact that it hads expected the delivery of weapons and supplies, but not personnel.

On 30 June the operational group met Colonel Hervieux, the leader of the resistance in the Vercors region, which had become a liberated 'republic' with an organised army of 5,000 men and women. The US operational group quickly decided that its highest-priority task would be the instruction of the resistance forces in the use of US and British weapons.

On 2 July a convoy of three armoured cars on the road linking Chabeuil and La Vacherie was ambushed, and 18 Germans were killed. Five days later, at Lus La Croix Haute, the 15 Americans and 30 resistance fighters selected a 300-ft (90 m) U-shaped section of road as an ambush site, and shot up a German convoy, When the Germans in trucks not caught in the ambush debussed and started to engage the Allied force, the operational group and its French allies pulled back to the assembly point. It was later learned that 60 Germans had been killed and 25 wounded, and also that three trucks and one bus had been destroyed.

On 14 July, Bastille Day, 85 Boeing B-17 Flying Fortress heavy bombers para-dropped 1,457 weapon, ammunition and equipment containers at Vassieux. Some 30 minutes later, and for the next four days, German aircraft bombed and strafed Vassieux, is landing strip and the town of La Chapelle, and in response the operational group moved into St Martin to organise the air defence of the Vercors plateau.

On 19 July German troops descended by glider on the landing strip at Vassieux. On the following day the operational group and 75 resistance fighters approached Vassieux, but were checked by the fire of German automatic weapons and the attacks of aircraft which bombed and strafed through the day. Fighting continued for three days, and in this time more than half of the 450 German airborne troops became casualties. The remaining Germans were pinned down, and two Junkers Ju 52/3m transport aircraft and one Junkers light bomber were brought down.

Between 23 July and 15 August, as the German forces first surrounded and then patrolled through the Vercors plateau, the operational group moved to the north toward the Chartreuse mountains. The men of the group spent 11 days in the woods, surviving on raw potatoes and occasional cheese. Finally, with resistance aid, the men of the group, in greatly weakened condition, reached the Belledonne mountains. Two days later the US force grew in size as 11 shot-down airmen joined the group.

Between 18 and 20 August German troop movements on the road linking Grenoble and Chambery were seen and reported, and a major power line to Lyon was demolished. On 21 August the movement of 5,000 German troops heading south from Chambery was reported to Major General John E. Dahlquist’s US 36^th Division, which had reached Grenoble as the eastern spearhead of Lieutenant General Alexander McC. Patch’s US 7^th Army in its advance from the 'Dragoon' (i) landing on the south coast of France, and the division launched an attack on this German force took 3,500 prisoners as the 1,500 other men were killed, wounded or dispersed into the hills.

On 24 August the operational group retired from the Belledonne mountains into Grenoble, and subsequently learned that the Germans had used 22,000 men in their 14-day Vercors attack, and had come to believe that was a US battalion rather than just the 15-man operational group in the area.