Those ads are a great way to monetize especially your german traffic!There are many Ad-Partners who provide Layer-Ads, but here you have a list of the most popular ones:

Layer-Ads.de

Details:
4€/1000 Layers for Visitors from Germany, 3€ for Austria and Switzerland
Layer-ads.de also pays for many many other countries, but much lower rates. Visit their website for more information.

Minimum Payout:
15 € - You can request 3 payouts per month. It normally takes about a week to receive your money per Paypal.

Euros4Click.de

Details:
You get 5 €/1000, but just for German, Austrian and Swiss traffic.

Minimum Payout:
20 €. You can request so many payouts you want and it just lasts 2-3 days to receive the money on paypal!