It would seem that the Paris Metro is subsidised:
http://www.newyorker.com/archive/1957/08/24/1957_08_24_082_TNY_CARDS_000257018
http://delong.typepad.com/sdj/2007/10/time-to-whomp-t.html
http://www.london.gov.uk/assembly/reports/transport/paris_report.pdf

Can't find by how much, though

Small info:
The Meteor project is, in effect, Line 14 of the Metro. It parallels both Line A and Line D between the city's main rail terminus for trains from the south and west of the country, Gare de Lyon and Chatelet.
The total cost of the project was €1 billion. The French national government and regional government of Ile de France each funded 35%, the Paris Transport Authority 18% and the departement of Paris the remainder.
http://www.railway-technology.com/projects/meteor/

In 1900 the first line, Line 1, was opened, with extensions following in order to serve the Exposition Universelle that year. The first 10 lines were built by the City of Paris and operated by the Compagnie du Chemin de Fer Métropolitain de Paris (CMP).
The Paris’ Métro remains under public ownership, with the Régie Autonome des Transports Parisiens (RATP) acting as both provider and transit authority.
The RATP spends millions cleaning up trains defaced by vandals. The agents are being hired under a government plan to create jobs for young people, under which the government will pay up to 80 percent of their wages.(= subsidised by the French government)