Is it permissible for Muslim men to use a perfume that contains synthetic saffron fragrance or synthetic saffron-derived ingredients? Does the ruling differ from using actual saffron in perfume?

If they extract the smell of saffron and put it in a fragrance and you use it, this is allowed. What is forbidden for men only is to do what is allowed for women, which is to put saffron on their bodies to adorn themselves with it (which gives that nice smell and color as well). This is what is forbidden on men