I have not, but my wife was involved in one - maybe sorta, you could say. My wife is a JP (so am I), and was asked by one of her staff to do the paperwork for her marriage. There wasn't going to be a ceremony as this staffperson is estranged from family. At the time, the staffperson in question identified as lesbian, while the spouse was a trans woman who had not physically transitioned. (I mentioned this to a friend whose reaction was, "But then... wait... how...?") Anyway, rather than just sign paperwork, my wife and the rest of the library staff got a cake and some food, and then decided to decorate, and next thing you know they actually threw them a nice, if somewhat improvised, ceremony and celebration. The spouse subsequently detransitioned and the staff member, I believe, identifies a bit more generally as queer now (they are still together). So whether it counts as a "same sex" wedding is a bit up in the air. There's a lot of fluidity in all of it.