Paris Seine river excursion discounts

On the Rail Europe website, one of the bonuses of a Eurail pass ( which includes France ) is a 50% discount on Seine river excursions with Bateaux Parisiens. However, on their website I can find no mention of a Eurail pass discount. I've emailed Bateaux Parisiens three times in the last 5 weeks but received no response. Does anyone know if they do indeed offer a discount, and is it on all cruises or only selected ones? I hope their boats are better than their customer service, or they'll be fishing us out of the Seine! Thanks,
Gary