I figured out I would go and browse the excellent peeringdb, but since it is user generated, I wouldn't find all autonomous systems and more importantly, scopes on which to filter networks were only regions.

So back to square one. The closest RIPE object that has a country field in it is the inetnum object. Then I just happened to remember that there was some obscure db file on the RIPE ftp (namely ftp.ripe.net), I found it here: ftp://ftp.ripe.net/ripe/dbase/split/ripe.db.inetnum.gz

...anonymous user, as for any public utility ftp. Well file is kinda heavy once ungziped, 830Mo or so, plain text.

Here's what a basic inetnum object looks like:
inetnum: 195.8.214.0 - 195.8.215.255
netname: DAILYMOTION-200610
descr: DailyMotion
country: FR
org: ORG-DM5-RIPE
tech-c: DM75002-RIPE
status: ASSIGNED PI
mnt-by: RIPE-NCC-HM-PI-MNT
mnt-lower: RIPE-NCC-HM-PI-MNT
mnt-by: NEO-MNT
mnt-routes: NEO-MNT
mnt-domains: DAILYMOTION-MNT
source: IPE # Filtered

there is actually a country flag, but I also need the IP range (you'll understand below, it is my only link to an aut-num), but I also need to take into account that there might be more than 1x description field between the country field and the inetnum field.

I'll ask grep to look into that, matching
country: COUNTRY-CODE and 4 lines above, which is:
grep -i -B4 'country: COUNTRY-CODE' /home/gregg/ripe.db.inetnum > tmpFile1
(as a hint you might want to run it with COUNTRY-CODE upper-case and lower-case, cause I didn't get the same results, even with the -i option...

Then, I want to keep only the inetnum in a separate list:
grep 'inetnum:' /home/gregg/tmpFile1 | cut -d' ' -f9 > tmpFile2

Which eventually gave me a list of all 1st IP within every RIPE range within the country I was looking for.

What I needed now is to get the aut-num corresponding with the IPs within this list. IP to AS# reversing is a common problem over the internet. You'll find many perl modules on CPAN for that, but I just loved the way the guys at cymru do it.

Then I ended up with launching:
netcat whois.cymru.net 43 < tmpFile2 > resultFile3

Whic after tidying a bit the ouput (mainly doing a uniq) provided me with a decent answer :/ There are certainly uncertainties with the grep -B4 part (i.e inetnum matching the country pattern, but with too many description fileds recorded), but that certainly can be tuned.

If anyone has a more efficient way, I'll take it as mine is not so reasonably funky.