Emmanuel Macron has been forced to wade into a snowballing row over claims French soldiers have been authorised to "open fire” if they come under life-threatening attack during Saturday’s 19th round of weekend “yellow vest” protests.

Preventing a repeat of last weekend’s violence, in which masked troublemakers wrecked dozens of stores and restaurants along the capital’s Champs-Elysées, is seen as a crucial test of the French president’s ability to restore order.

Christophe Castaner, his embattled interior minister, this week announced the decision to draft 3,000 soldiers to protect hot spots in Paris and other big cities on Saturday.

Failure to maintain order prompted Mr Castaner to fire the…