British luxury watchmaker Backes & Strauss targets France British watchmaker Backes and Strauss, also the world's oldest diamond maker, has entered into a partnership with French diamond company Waskoll to open up the French market for its diamond-studded watches priced between 15,000 and 1.5 million euros. Bespoke pieces can be more expensive. Backes and Strauss produces around 1,000 watches per year. IMAGES AND SOUNDBITES.