Sometimes in large cities where the airport is not in the centre, it
is possible to check in for a flight at a special ticket counter in
the city centre, such as at a train station connecting the centre to
the airport.

By check-in, I mean a counter that accepts the luggage and issues the
boarding pass -- just like in the airport, and then handles the
transport of your luggage from the city centre all the way to the
airplane.  Thereby one can be free of luggage to enjoy the city for a
few more hours, and also not have to wait later in the queues at the
airport (except for security, of course).

So, my question is, whether there is such a check in counter in
central Paris? (the station, Gare du Nord, seems a likely spot).  If
there is a city check in, does it currently serve international
flights on Air France or Cathay Pacific travelling to Hong Kong?

[For example, here in Hong Kong, there are 2 rail stations where you
can check in for an airplane flight -- but of course since 9/11, some
of the airlines closed their city check-in counters whereas others
have kept theirs open.  Therfore, current information is important]

It should be possible to answer this question with a few phone calls
or web site visits. Please cite any web sites that you dig up.

I have already found web sites that explain how to get to the airport
on the metro, but none mention city check in. These aren't so useful.

I don't want to take the money from the researchers' team, but as
nobody seams to work on it : I am pretty sure that there is no such
service in Paris (I live there).
Sorry about it, but you'll have to go to the airport with your
luggage...

thanks for the info.