Could it be Agent Aika? It features the main character (older woman) Aika and her partner Rion. There's a lot of fan service, especially panty shots and bra shots. It was released as an OVA in 1997 but was aired on several German TV channels.
The character designs practically make it impossible not to see panties
Anime News Network
I also find Aika to be the most likely candidate as it is the epitome of the panty shot anime.
However, there is also another candidate which fits the description: Aika's spiritual successor Najica Blitz Tactics which ran on the other German music TV station Viva in 2004.
Produced by the same studio (Fantasia) under the same director (Katsuhiko Nishijima) ...
Aika and Najica are the most likely answers -- Noir has handguns, short skirts and occasional fanservice, but zero panty shots -- but I have a third guess:
Kiddy Grade is a 2002 science fiction series about two superpowered interstellar secret agents for the Galactic Organization for Trade and Tariffs, Éclair and Lumière. It's pretty heavy on ...