This is available for sale on Steam/GOG, but it's the VGA version. I took the time to hunt down the SVGA version by acquiring the original disk, fully set it up for dosbox: correct cycles based on recommended CPU, using builtin mt32 emulation for midi music, etc., It supports both windows and linux out of the box. For linux, you need to install dosbox-staging from your package manager. For windows, it comes with a copy of dosbox-staging. You should be able to play the game just by double-clicking the win_run.cmd
Save files are placed in the 'saves' directory. The game technically requires the original CD to run, but only to access the movie files. I've repackaged that as a single .iso to reduce the size, the launcher handles all that, don't worry.
Note that I assume you already own a license to play the game if you are going to download this! This is for people who wish to play the SVGA version rather than the VGA version. Also, it's probably setup much better than the Steam/GOG install. Do not download if you do not own the original game! 
Theirs:
Note the stretching! They didn't even do any aspect ratio correction for the display or the pixels!
Ours:
If you do not like the scanlines, you can disable it in the dosbox.conf file by setting glshader to none instead of crt-auto. Note that you have to view the screenshot at 100% to not see banding artifacts caused by the crt shader when scaled down, the artifacts are not present when ingame of course.
Let me know if you have any issues.
I much prefer the original French title, btw: Time Gate: The Secret of the Templar
If you'd like to learn more about the game or just want something to listen to while you wagie, here's a video:
