We are big tennis fans and have been to the US Open (several years ago) and Australian Open (this year).  We will be in London for a month next May and my husband suggested we take a few days to go to Paris by train and see the Open.  We like to see the early rounds with a grounds pass---that worked well for us in the previous two.  Can anyone help me get started with the research?
When do the grounds passes go on sale---is it still March as in previous years?  for lodging, we would like to walk to the venue if possible, so thinking of staying in the 16th.  Is this a bad idea?  I know we could stay farther away and use the Metro, but I really do not care for subways.  We have walked up to 10 miles a day in Paris before.  We really won't have any other goals for this short visit (no museums, etc.)
Thanks for your help!