During January and February 1885 the besiegers were able to place enormous pressure on the garrison because the bulk of the Tonkin Expeditionary Corps was committed to the Lang Son Campaign (February 1885).
 However, the capture of Lang Son on 13 February 1885 allowed the French to come to the relief of Tuyen Quang.

General Brière de l’Isle personally led Lieutenant-Colonel Laurent Giovanninelli's 1st Brigade back to Hanoi, and then upriver to the relief of Tuyen Quang.
The brigade, reinforced at Phu Doan on 24 February by a small column from Hung Hoa under the command of Lieutenant-Colonel de Maussion, found the route to Tuyen Quang blocked by a strong Chinese defensive position at Hoa Moc.

On 2 March 1885 Giovanninelli attacked the left flank of the Chinese defensive line.
The Battle of Hoa Moc was the most fiercely fought action of the Sino-French War.
Two French assaults were decisively repulsed, and although the French eventually stormed the Chinese positions, they suffered heavy casualties.
Nevertheless, their costly victory cleared the way to Tuyen Quang.
The Yunnan Army and the Black Flags raised the siege and drew off to the west, and the relieving force entered the beleaguered post on the afternoon of 3 March.

Three days earlier, on 28 February, the Chinese had made a seventh and final assault on the Tuyen Quang perimeter.
 Knowing that the relief column was close and that it would be their last chance to capture the post, the Chinese attacked with fanatical courage but once again failed to force the breach.
 On 2 March the men of the Tuyen Quang garrison listened anxiously to the sounds of rifle and cannon fire from the Yu Oc gorge, where the 1st Brigade was fighting to break through to the beleaguered post.
 Hopes of relief faded as the sounds of battle continued well into the night.
 It seemed all too likely that Giovanninelli's men had been halted by the Black Flags.

On the morning of 3 March, to their amazement, the defenders awoke to find that the Chinese had abandoned the siege.
 Dominé sent out fighting patrols to scout the enemy trenches.
 The last French fatality of the siege was suffered during a skirmish with a small Chinese rearguard.
 Legionnaire Striebler saw a Chinese soldier sighting on Captain de Borelli and threw himself between the two men.
 Striebler was killed instantly by the bullet intended for his captain.
 The incident, unsurprisingly, haunted de Borelli for the rest of his life.
 Several years later he made what amends he could by publishing a moving poem to the fellowship of the French Foreign Legion, A mes hommes qui sont morts.

The arrival of the relief column on the afternoon of 3 March was greeted with jubilation by the defenders.
 Captain Jean-François-Alphonse Lecomte, who had marched with Giovanninelli's brigade, recorded the encounter between Captain de Borelli and General Brière de l'Isle:
We approached the fortress.
 At the head of a group of officers we saw a captain with a long white beard, who was flourishing his cane and dancing an impromptu jig.
 The first man he met in the relief column was a bugler.
 He threw his arms around him.
 Then he embraced the second bugler.
 The band tried to keep its dignity, but to no avail.
 He then abandoned the buglers and fell on the neck of the first drummer.
 For a moment the drum stood between him and the object of his affections, but eventually he managed to plant two loud kisses on the drummer’s cheeks.
 Then he made for the general-in-chief.
 There was a sudden hush, as when an orchestra falls silent at the end of a dance.
 He recovered himself, solemnly clicked his heels, and saluted General Brière de l’Isle.
 We recognised Captain de Borelli.

"Good afternoon, Captain, how are you?
 We’re delighted to see you!"

"Indeed!
 Me too!
 Especially as I only just escaped being killed this morning!"
During January and February 1885 the besiegers were able to place enormous pressure on the garrison because the bulk of the Tonkin Expeditionary Corps was committed to the Lang Son Campaign (February 1885).  However, the capture of Lang Son on 13 February 1885 allowed the French to come to the relief of Tuyen Quang.
General Brière de l’Isle personally led Lieutenant-Colonel Laurent Giovanninelli's 1st Brigade back to Hanoi, and then upriver to the relief of Tuyen Quang. The brigade, reinforced at Phu Doan on 24 February by a small column from Hung Hoa under the command of Lieutenant-Colonel de Maussion, found the route to Tuyen Quang blocked by a strong Chinese defensive position at Hoa Moc.
On 2 March 1885 Giovanninelli attacked the left flank of the Chinese defensive line. The Battle of Hoa Moc was the most fiercely fought action of the Sino-French War. Two French assaults were decisively repulsed, and although the French eventually stormed the Chinese positions, they suffered heavy casualties. Nevertheless, their costly victory cleared the way to Tuyen Quang. The Yunnan Army and the Black Flags raised the siege and drew off to the west, and the relieving force entered the beleaguered post on the afternoon of 3 March.
Three days earlier, on 28 February, the Chinese had made a seventh and final assault on the Tuyen Quang perimeter.  Knowing that the relief column was close and that it would be their last chance to capture the post, the Chinese attacked with fanatical courage but once again failed to force the breach.  On 2 March the men of the Tuyen Quang garrison listened anxiously to the sounds of rifle and cannon fire from the Yu Oc gorge, where the 1st Brigade was fighting to break through to the beleaguered post.  Hopes of relief faded as the sounds of battle continued well into the night.  It seemed all too likely that Giovanninelli's men had been halted by the Black Flags.
On the morning of 3 March, to their amazement, the defenders awoke to find that the Chinese had abandoned the siege.  Dominé sent out fighting patrols to scout the enemy trenches.  The last French fatality of the siege was suffered during a skirmish with a small Chinese rearguard.  Legionnaire Striebler saw a Chinese soldier sighting on Captain de Borelli and threw himself between the two men.  Striebler was killed instantly by the bullet intended for his captain.  The incident, unsurprisingly, haunted de Borelli for the rest of his life.  Several years later he made what amends he could by publishing a moving poem to the fellowship of the French Foreign Legion, A mes hommes qui sont morts.
The arrival of the relief column on the afternoon of 3 March was greeted with jubilation by the defenders.  Captain Jean-François-Alphonse Lecomte, who had marched with Giovanninelli's brigade, recorded the encounter between Captain de Borelli and General Brière de l'Isle:
We approached the fortress.  At the head of a group of officers we saw a captain with a long white beard, who was flourishing his cane and dancing an impromptu jig.  The first man he met in the relief column was a bugler.  He threw his arms around him.  Then he embraced the second bugler.  The band tried to keep its dignity, but to no avail.  He then abandoned the buglers and fell on the neck of the first drummer.  For a moment the drum stood between him and the object of his affections, but eventually he managed to plant two loud kisses on the drummer’s cheeks.  Then he made for the general-in-chief.  There was a sudden hush, as when an orchestra falls silent at the end of a dance.  He recovered himself, solemnly clicked his heels, and saluted General Brière de l’Isle.  We recognised Captain de Borelli.
"Good afternoon, Captain, how are you?  We’re delighted to see you!"
"Indeed!  Me too!  Especially as I only just escaped being killed this morning!"
Siege of Tuyên Quang