I heard this was planned and my train goes on the 18th, does anyone know if it's happening?
I am not aware of anything like that. It happened last week but taxi protests usually don't last that long, if only because they often get a much softer treatment from the government than rail workers. However, I guess it's possible they would stage another protest exactly one week after the first one.
Also note that only public sector employees and civil servants have to officially warn before going on strike (“préavis de grève”). Private sector employees can just go on strike without warning and many taxi drivers are not employees or protested with their employer's approval (they did announce last week's protests in advance, though). So they might stop working or even disrupt traffic illegally without forewarning (in the past, farmers or truck drivers did that too without always publicly announcing precisely where they would put roadblocks).