1- He is going ||to Paris|| next week. [tell us where he is going, to is a preposition]
2- He is going ||to|| travel ||to Paris||. [tells us he is not sailing or walking or bicycling to Paris,for example]
Both verbs in both sentences are in the present continuous tense used as a future. Sentence 2 has a verb phrase after to.
What comes after the function word to shows the objective. travel to Paris is not part of the main verb. It is a verb phrase. Some would call it a predicate. It can be contrasted with other verbs: to ride to Paris, cycle to Paris, fly to Paris
We commonly refer to this as "going to" used as a future but strictly speaking that is wrong.
Also, note in 1) to is a preposition. In 2) to is a functional operator that precedes the verb or verb phrase.
Going in the continuous as a future (or present!) is:
I'm going [now:present or tomorrow:as future]
Nothing that comes after the word TO has anything at all to do with the continuous present of go used as a future in the OP's sentences.