I must have read this some time in the 70s. Not a picture book, I would say this book was middle grade fiction (aimed at 8-12 year-olds). I’m guessing I read it between the ages of 9 and 11. It took place in Bern, Switzerland, and although I think the protagonist may have been a young girl, there was definitely a clockmaker in it, and his shop. I don’t think it had any elements of fantasy in it, but I remember finding it a magical story. I wish I remembered more about it, but that’s about all I’ve got!