Why did the arrest of two parlementaires cause an uprising in Paris in August 1648?

The arrest of two outspoken parlementaires on August 26, 1648, by the government of Jules, Cardinal Mazarin and the queen regent, Anne of Austria, served as the catalyst for an uprising in Paris because it directly challenged the Parlement of Paris's ongoing efforts to limit royal authority.1

Earlier in 1648, the Parlement had sought to establish constitutional checks on the monarchy, including the right to modify royal decrees, the abolition of the intendants, and an end to arbitrary imprisonment. Although the government had reluctantly agreed to many of these reform demands in July, the subsequent arrest of the two magistrates—following news of a military victory over the Spanish—was perceived as a provocative reversal of those concessions. The resulting popular uprising in Paris forced the government to release the two men just two days later, marking a significant escalation in the Fronde, a series of civil wars that sought to resist the centralizing policies of the royal government.1