I stayed at the Alt Hotel for a weekend, which is right down the road from La Bête à Pain.
As part of an Alt Hotel package, you can opt to have a breakfast coupon for La Bête à Pain, so that's what I did.
And for two days in a row I enjoyed nice croissants (with salmon and more!), juice, coffee, espressos, and cappuccinos to start my mornings with my travel companion, and it was well worth it!