Visit the cyclingfans.com site. They list live streams.
http://www.cyclingfans.com/paris-roubaix/live
Some are legal and some aren't and many are geo restricted. To get around the geo restrictions download VPN software. I used Windscribe on IOS though they have software for other OS/browsers. It is free up to a certain point and worked well for me.
Last week I watched Tour of Flanders from french TV using VPN setup to servers in France and it worked well.
This week NBC sports as I have a cycling pass to watch the Tour and UCI cyclocross. It is a good deal and works very well.
Alan