With peace declared d'Acier involved himself in the conspiracy of Meaux that attempted to seize the king and execute his leading militant Catholic advisers.

Wounded at Poitiers he was made colonel-general of the Protestant infantry, before being captured at the Battle of Moncontour Released thanks to the efforts of his brother Crussol he would survive the Massacre of Saint Bartholomew through the protection of his wife and sister-in-law.

[3][4] Together they had the following issue: Early in 1562 while his brother was working to ensure the south of France complied with the king's edicts, d'Acier accepted an offer from the Protestant church of Languedoc to be its military protector.

[6] In November 1562 his brother Crussol was persuaded to assume the role of governor of Languedoc by the Protestants, he quickly installed Beaudiné as the lieutenant-general of the region.

Damville installed Catholic town councils across the region as its governor, ignoring the vehement protests of Crussol and d'Acier.

[8] D'Acier was among the Protestant nobles who conspired to arrange the Surprise of Meaux with his role being to rise up in the south concurrently to the capture of the king and seize the towns of Languedoc.

[14] Arriving at La Rochelle following his flight from court in late 1568, Condé put out the call for Protestant forces to be assembled and come to his aid.

[5] As the Massacre of Saint Bartholomew unfolded, d'Acier who had come to the capital for the wedding was protected by his wife and sister in law, both of whom were close to the court.

[21] In 1573 his brother Crussol died from an illness developed during the siege of La Rochelle, leaving the title of duc d'Uzès vacant.

[5][22] After the conclusion of the fourth civil war, d'Acier was charged in his role as Lieutenant-General of Languedoc to bring the Huguenots of the region back into obedience with the crown and the peace edict.

The Malcontents (France), consisting of moderate Catholic and Protestant nobles conspired against the crown, however their plot was uncovered and civil war resumed.