French ambulance drivers hold blue, white, red smoke bombs during a demonstration at the Place de la Concorde in Paris, France, December 3, 2018. Ambulance drivers in Paris staged a surprise protest on Monday against the social security reforms they believe would severely impact their livelihoods, as the ''yellow vest'' protests continue. REUTERS/Gonzalo Fuentes

French ambulance drivers block traffic during a protest demonstrartion near the National Assembly in Paris, December 3, 2018. After a weekend of intensified protests, unrest in Paris still rages on. Ambulances blockaded roads on Monday - their drivers angry about President Emmanuel Macron's overhaul of the country's healthcare system. REUTERS/Gonzalo Fuentes

French ambulance drivers block traffic during a protest demonstration at the Place de la Concorde in Paris, December 3, 2018. Ambulance drivers in Paris staged a surprise protest on Monday against the social security reforms they believe would severely impact their livelihoods, as the ''yellow vest'' protests continue. REUTERS/Gonzalo Fuentes

French ambulance drivers face off with French gendarmes during a demonstration at the Place de la Concorde in Paris, December 3, 2018. After a weekend of intensified protests, unrest in Paris still rages on. Ambulances blockaded roads on Monday - their drivers angry about President Emmanuel Macron's overhaul of the country's healthcare system. REUTERS/Gonzalo Fuentes

French ambulance drivers face off with French riot police during a demonstration at the Place de la Concorde in Paris, France, December 3, 2018. Ambulance drivers in Paris staged a surprise protest on Monday against the social security reforms they believe would severely impact their livelihoods, as the ''yellow vest'' protests continue. REUTERS/Gonzalo Fuentes

French riot police take position during clashes with French ambulance drivers as part of a demonstration at the Place de la Concorde in Paris, France, December 3, 2018. After a weekend of intensified protests, unrest in Paris still rages on. Ambulances blockaded roads on Monday - their drivers angry about President Emmanuel Macron's overhaul of the country's healthcare system. REUTERS/Gonzalo Fuentes