Hi! If your friend was telling you "Paris is a right mess!" he was probably expressing frustrations - as have other Parisians to us, that they are getting tired "of this nonsense". I can go more into detail what different French citizens in Paris have told us, but for the worried tourists, I can assure you, that the strikes and demonstrations will most likely have little to no impact on you.
We were there during Spring Break, and had the best time. We were staying in the 6th. The garbage pick up from the weeks prior had just been completed (though some streets still needed an "after cleaning"), and the whole city was full of tourists from all over the world, as usual. The Paris marathon took place. There were no security issues or concerns. All tourist sites were open. We were lucky to avoid a full strike day completely so we did not experience any transportation issues, other than some stops on the RER C were closed, however, this appeared to be due to extensive renovations (until late April- a sign on a closed station said). The metro appeared to work normally. Line 1 (yellow) always operates since it doesn't have drivers. The next "general strike day" will be announced immediately after the last one (it's actually April 13, today), so expect an announcement later today!
The strikes have taken place once a week, on a weekday. There was also a three day air traffic controller strike that ended just before we arrived, but in general; flights in and out of Orly are more likely affected than in and out of CDG. If you have train tickets within France, you could also be affected. If you know this ahead of time, consider changing to a different day from the "general strike day", if feasible. On strike days the metro within the city does not appear to be affected much, but the RER lines might be. As far as I'm aware, the Eiffel Tower was only closed a single day since the strikes began in January. The Louvre opened late a few times and was closed once during a general strike day. If you are in Paris on a general strike day, ask locals what the route (beginning and end point) is, and avoid particularly the end point. The demonstrations have always been beginning and ending at the very large squares on the right bank (but not Place des Vosges).
I wish everyone a wonderful time in Paris!