"It is awesome that you went to Paris!"
Translation: C'est génial que tu sois allé à Paris ! Pourquoi ce n'est pas, C'est genial qu'il aies été à Paris?
So much easier to say Tu es allé à Paris ? C'est génial ! and avoid the subjunctive all together :).
Sometimes the subjunctive is unavoidable but, in most instances, you can sidestep it. After reading through reams of posts on WordRef, it is clear that even the French try to avoid it wherever possible when speaking (though it is common in written French).
I still would have got that one wrong. :p I would have said: Tu as été à Paris? -.-. (I have to practice this one a lot I guess. )
'Aller' prend l'auxilaire Être, pas Avoir. Aussi, tu as mis 'il aies', pas 'tu aies'
- Sounds a bit formal to use as voyagé → "travelled"
- It would still need the subjunctive past tu aies voyagé as it is the it is + adjective + that structure → c'est génial que that triggers the subjunctive as the adjective takes the value of a judgment or opinion.