They are both correct English sentences, however I do not see them as being identical in meaning. Normally 'I have never been to Paris before' would imply that the speaker was currently in Paris, or was at least actively planning a trip to Paris. Adding 'before' implies that the past was different to now and the situation has now changed, so 'I have never been to Pairs before' I would understand as 'this is my first trip to Paris'. 'I have never been to Paris' simply means 'at no stage in life have I ever been in Paris, I am not there now and have never been in the past'

You can use both. But I’d ask before when ? You could add the word “now” and that would be good too.