Tehreek-e-Labbaik Pakistan chief Saad Hussain Rizvi arrested by police on Monday in Lahore.
Police said Rizvi was detained to maintain law and order.
Protests broke out in Lahore and other parts of Pakistan following the development.
Thousands of protesters blocked streets and intersections in Lahore.
Police used tear gas and water cannon to disperse the protesters.
Traffic movement was severely affected in cities across Pakistan due to ongoing protests.
TLP is a far-right Islamist political party in Pakistan.
It has been demanding expulsion of the French ambassador from Pakistan.
TLP is opposing publication of blasphemous caricatures in Charlie Hebdo magazine and remarks about Islam and terrorism by French President Emmanuel Macron.
TLP said Imran Khan Government has "turned back on its promise" to expel the French envoy.