I was there 3 years ago. Great place for a holiday.
Flew with Air France via CDG, probably the best route. It is along journey but you got those seat back tv's which are great to pass the time.
Try not to spend a huge amount of time in Varadero; it is really a sort of artifical Cuba; just another Caribbean beach resort but with awful food. If you are going just for a beach holiday, you would be better off going somehere like Barbados or Bahamas instead.
I spent a couple of days in Havana, then spent a week travelling around the country in a hire car; best way of getting around, then back to Havana for a few more days before flying home.
Places, I would recommend visiting: Havana, Vianles & Trinidad. By far my favorite place was Vinales in the west of the island; stunning scenary.
Oh you have to try the Mojitos; great drink made from Cuban rum