Are there couples in france willing to accomodate other couples from other countries for a short stay?

my husband & i are touring Paris for 4 days and are trying to meet a young couple who will show us around (not all day)and maybe accomodate us, if possible. We are willing to pay for accom & our expenses. In return, we will do the same for the other couple when visiting our country, South Africa.

Yes, there are, but you are not very likely to find them on this site which is essentially English. You could post your question on the French section (Click on French flag at the bottom of this page).
Heading
Y a-t-il des jeunes couples pr茅par茅s 脿 recevoir d'autres couples d'un pays 茅tranger et qui pourraient leur faire visiter Paris?
Additional info:
Ce serait pour environ quatre jours.
Nous sommes pr茅par茅s 脿 payer pour nos d茅penses et nous ferions la m锚me chose pour eux s'ils venaient en Afrique du Sud.

Personally I would be very careful about this as you may open yourselves to being exploited. It is a bit like a blind date without any guarantees.
Couchsurfing has met considerable problems including credit card fraud.
http://en.wikipedia.org/wiki/CouchSurfin...
Have you considered staying in a special centre devised for young people? When I write "young" I take my students to such a centre and there are many middle age couples who stay there too. They are cheap, comfortable, clean, and offer all sorts of facilities, including double rooms. The one I use is called Centre Jean Monnet
http://www.fiap.asso.fr/
Click on the American flag at the top to get the English version of what they offer.

Check out couchsurfing.com