Emperors Valentinian II, Arcadius, and Theodosius I issue a new law banning circuses on Sunday because that would create a distraction for Christians.
According to this law:
"Contests in the circuses are prohibited on the festal Days of the Sun (Sundays), except on the birthdays of Our Clemency, so there will be no crowds which can divert men from the worship and mysteries of the Christian faith" [CTh 2.8.20]
This law benefits Christians over non-Christians in a couple of ways. First, insofar as contests are a distraction, only Christians get to have the distraction eliminated; pagans and Jews can still be distracted on their Sabbath or holy days.
Second, by eliminating one of the things which people might find to do on Sundays, it becomes easier to get them into church. For pagans and Jews, worship is more inconvenient because there are other things they could be doing — things that now won't happen on Sundays when they would otherwise be free.