Darcs may very easily be obtained on the web, at http://darcs.net . After installing darcs on your system, cd to a directory where you store your sources, e.g. ~/Sources and type
% darcs get --lazy http://hub.darcs.net/zaleski/paris-stable
then as further patches are released they may be obtained by doing
% cd ~/Sources/paris-stable
% darcs pull http://hub.darcs.net/zaleski/paris-stable
PARIS is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. PARIS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public Licence for more details.