At least two preconditions are needed for paras to appear: 1) Static-Line Parachuting, which was developed in Italy in the 1920s, and 2) Suitable aircrafts.
I think with WWI technology, there could still be small, commando-style raids tried with biplanes or even gliders. But large scale drops behind the enemy line could not be developed until large slow-moving aircrafts like Tupolev TB-3 was employed.
So, if the determination to develop parachuting warfare was there, could the Tactical questions be quickly solved with WWI technology? For instance, could WWI bombers be used for parachuting?