Assuming you have your 4 BA segments, there are presumably other ways of getting 20 TP's from Paris - a trip to Budapest on Malev or a trip to Spain on IB - should you want to make a holiday of it.

And once you have BA Silver, you are well placed for any status matches with other alliances that come along next year as well.

One other key thing, of course. Assuming your account is Europe based, you will be able to retain Silver for the next 2 years with just 400 tier points. Otherwise, you will need 800 points under the new structure.