Wired Sensor Communication Protocols
I know that RS-485 is a proper answer for your question, not only that, but I have personally used RS-485 networked sensors in several installations that worked for years. And there are lots of sensors using RS-485.

I learned the hard way that for noisy environments shielded conductors are important as is single point of connection of the shield to ground (close to the host). Avoid multiple ground connections for long networks.

Regarding CE, it is as simple as googling RS-485 CE certified sensors or something like that. I have already tried by myself and there are many hits.