OK let me see if I manage to make myself understood...
First - the sentence has a misspelling, it should be:
..."e estou radiante em ver a cidade Luz retra
tada pelo carnavalesco Luz."
That "retratada" means "portrayed", "described". Therefore it does
not mean "illuminée"
Second - the "carnavalesco" is usually a plastic artist (nowadays, because it used to be less pro).He is the person in charge of the artistic theme of the Samba School,
S/he creates, designs all the costumes the members of the group will wear during the parade according to that "theme" they will develop.
It's a titanic work since there are about 4/5000 people in each group, divided in about 30 "wings" each wing with a different costuming.
That person also idealizes the floats (those huge structures that complete the parade called "carros alegóricos" ).
I don't think the word could be translated after all. A possible name to identify that person could be: "Maître du Carnaval"
So, the whole sentence should read IMHO :
"...et je suis ravi de voir la ville lumière
illustrée par le Maître Lumière du Carnaval."
We should not forget that "Luz" may be the proper name of that "carnavalesco" and the person writing uses that to make a parallel with the "ville lumière" for Paris.
Just to have some more information on how we celebrate Carnival
have a look here.
That's the view a foreigner got after spending a Carnival in Rio.
I hope you can find a better option.