More broadly, they were fined because of the European and especially French culture of the left wing where a business generally owns their customers and an employee owns his job. How dare you liberate these consumers by offering them a choice? They are OURS. Doubly so because Uber is so terribly un-French. We will have our friends in the government protect ourselves from this theft.
Mind you, it's not as bad as, say, the teachers in Mexico who can sell their job to someone else, but... it has an impact on the economy, and it's a major reason youth unemployment is so high (and a contributing factor to why immigrant communities can't integrate, which is a contributing factor to the security situation over there...)