To be honest, I am not sure whether they carry simmaq, as I do not use it too often, but they do carry zatar (a mixture of thyme, simmaq, and sesame seeds) so I would guess they carry the former. You could try calling them on 043 538 36 11 to check. The owner speaks German, English, Arabic, and likely French as well.

For the record, I have no affiliation with the store or the owners, just happy to find it and I like supporting small business owners.