From London's black cabs to taxis in Rome, Paris, Berlin and Milan, chaos is expected in key European cities as traditional cabbies protest a rise in unlicensed drivers and chauffeur services that are chipping away at their client base.
California-based chauffeur car company Uber is the main target of the drivers' ire, but it is only one of many new smartphone-dependent car services seen as bypassing strict regulations faced by licensed drivers.
"Uber is deliberately not respecting regulations and on top of that has significant financial means," said Serge Metz, chief executive of France's Taxi G7.
The protest comes just days after Uber was valued at a whopping $17 billion (€12 billion), one of the highest ever figures for a technology startup.
Launched in 2009, the Uber app allows clients to connect directly with "black car" services, a thriving model which has seen it and similar companies surge across the globe.
In France there are now an estimated 10,000 vehicles and motorcycle taxis run by such non-traditional taxi firms. Drivers are only allowed to pick up passengers through prior reservation, not by hailing them in the street. Most notably, they don't have to shell out some €240,000 for a license required by official taxi owners.
Fury at the practice has seen taxi drivers stage several protests, choking major roads across France - a sight expected again Wednesday, when a separate train workers' strike will compound traffic problems.
Drivers will converge on the two main airports in Paris, Charles de Gaulle and Orly and slowly head into the city, taxi federations said.
In Rome, taxi drivers will hold a "reverse strike" by charging only €10 per trip to fall in line with competitors' prices. In Milan, drivers will strike all day. Convoys of taxis are expected to block traffic in Berlin and Hamburg.
In a jaunty response to the protest, Uber said it would offer 50 percent off its services in Paris, in an email to subscribers.