I just noticed that you can watch a variety of Arte documentaries online. While their main focus is obviously French and German, there also seem to be an English and Spanish selection.
For instance, they're peddling this playlist with a historical focus, although many of the videos come with a friendly "Cette vidéo n'est pas disponible dans votre pays." Luckily, as is often the case with these kinds of blocks, youtube-dl doesn't care. Find an individual video, for instance the one on Alexander the Great. Then use youtube-dl on it:
youtube-dl http://www.arte.tv/guide/fr/050298-000-A/alexandre-le-grand
And presto, one geo-blocked video is parked on your HDD.
However, it seems youtube-dl defaults to downloading German-language videos. I think it'd be better if it defaulted to the original language or something. To figure out the available languages, use the --list-formats option:
$ youtube-dl --list-formats http://www.arte.tv/guide/fr/050298-000-A/alexandre-le-grand
[arte.tv:+7] 050298-000-A: Downloading webpage
[arte.tv:+7] 050298-000-A: Downloading player page
[arte.tv:+7] 050298-000-A: Downloading JSON metadata
[arte.tv:+7] 050298-000-A: Checking HLS_XQ_1 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_MQ_1 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_HQ_1 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_MQ_2 video format URL
[arte.tv:+7] 050298-000-A: Checking HLS_XQ_2 video format URL
[arte.tv:+7] 050298-000-A: Checking HLS_SQ_2 video format URL
[arte.tv:+7] 050298-000-A: Checking HLS_SQ_1 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_SQ_2 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_HQ_2 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_SQ_1 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_EQ_1 video format URL
[arte.tv:+7] 050298-000-A: Checking HTTP_MP4_EQ_2 video format URL
[info] Available formats for 050298-000-A:
format code extension resolution note
HLS_XQ_1 m3u8 1280x720 VF, Français (Doublé) 2200k
HLS_XQ_2 m3u8 1280x720 VA, Allemand (Doublé) 2200k
RTMP_HQ_1 flv 720x406 VF, Français (Doublé) 800k
RTMP_HQ_2 flv 720x406 VA, Allemand (Doublé) 800k
HTTP_MP4_HQ_1 mp4 720x406 VF, Français (Doublé) 800k
HTTP_MP4_HQ_2 mp4 720x406 VA, Allemand (Doublé) 800k
RTMP_MQ_1 flv 384x216 VF, Français (Doublé) 300k
RTMP_MQ_2 flv 384x216 VA, Allemand (Doublé) 300k
HTTP_MP4_MQ_1 mp4 384x216 VF, Français (Doublé) 300k
HTTP_MP4_MQ_2 mp4 384x216 VA, Allemand (Doublé) 300k
RTMP_EQ_1 flv 720x406 VF, Français (Doublé) 1500k
RTMP_EQ_2 flv 720x406 VA, Allemand (Doublé) 1500k
HTTP_MP4_EQ_1 mp4 720x406 VF, Français (Doublé) 1500k
HTTP_MP4_EQ_2 mp4 720x406 VA, Allemand (Doublé) 1500k
HLS_SQ_1 m3u8 1280x720 VF, Français (Doublé) 2200k
HLS_SQ_2 m3u8 1280x720 VA, Allemand (Doublé) 2200k
RTMP_SQ_1 flv 1280x720 VF, Français (Doublé) 2200k
RTMP_SQ_2 flv 1280x720 VA, Allemand (Doublé) 2200k
HTTP_MP4_SQ_1 mp4 1280x720 VF, Français (Doublé) 2200k
HTTP_MP4_SQ_2 mp4 1280x720 VA, Allemand (Doublé) 2200k (best)
Here we see why it picks German; it's considered "best". Quality-wise it's obviously equivalent to the French one, so if you want that one instead you have to copy the relevant quality string:
youtube-dl --format HTTP_MP4_SQ_1 http://www.arte.tv/guide/fr/050298-000-A/alexandre-le-grand
Slightly roundabout, I admit. I'm thinking of writing a quick shell script to download the high res video in one language, the low res in another (assuming the audio quality never changes) and to merge it all together so you can switch at will. That's what I'm used to on Arte via sat, après tout.
Edit: alas, no such luck.
$ ffmpeg -i Alexandre\ le\ Grand-050298-000-A-french.mp4
[…]
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 125 kb/s (default)
$ ffmpeg -i Alexandre\ le\ Grand-050298-000-A-low.mp4
[…]
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 61 kb/s (default)
Edit 2:
Also, they don't have separate subtitles. I noticed some videos have subtitles, but they're encoded into the video.
$ youtube-dl --list-formats http://www.arte.tv/guide/fr/058948-000-A/tchernobyl-fukushima-vivre-avec
[…]
HLS_XQ_8 m3u8 1280x720 VOF-STMF, Version française - ST sourds/mal 2200k
RTMP_HQ_8 flv 720x406 VOF-STMF, Version française - ST sourds/mal 800k
HTTP_MP4_HQ_8 mp4 720x406 VOF-STMF, Version française - ST sourds/mal 800k
RTMP_MQ_8 flv 384x216 VOF-STMF, Version française - ST sourds/mal 300k
HTTP_MP4_MQ_8 mp4 384x216 VOF-STMF, Version française - ST sourds/mal 300k
RTMP_EQ_8 flv 720x406 VOF-STMF, Version française - ST sourds/mal 1500k
HTTP_MP4_EQ_8 mp4 720x406 VOF-STMF, Version française - ST sourds/mal 1500k
HLS_SQ_8 m3u8 1280x720 VOF-STMF, Version française - ST sourds/mal 2200k
RTMP_SQ_8 flv 1280x720 VOF-STMF, Version française - ST sourds/mal 2200k
[…]