I'm hoping an FT'er from Sixt can help me out here.

We're trying to book a car for rental in France (drop off in Germany). We would also like to avail the 15% off and car upgrade with elite status (on Qatar Airways). The office in Dubai was not of much help - they had a limited selection of cars available for rental in Paris, at a price higher than what is available online, and said they wouldn't be able to offer the above mentioned discount.

We also specifically need unlimited mileage, and I couldn't find a way to get that when trying to book on the website. Any advice, suggestions or help would be appreciated.