Just to update / add....
My mistake! You can get google earth cache finding option without being a premium member. A friend has just shown me, it's on the right hand margin of your profile page. (Click on download google earth, and you can just choose the 'open' option if you already have google earth on your computer. easy!). I was expecting to find it on the 'hide and seek' page . So, more than a month into my geocaching... I am now finding the initial planning part of the process a lot easier ! Hope that may help another newbie!
When I was just doing a keyword search, failed to find any near the Gare du Nord in Paris (we just had a reasonably short stopover). Checking back on google earth confirmes that there aren't any. But we managed a few in London before we hopped on the Eurostar, so all was not lost!
Clare