ok, this took me a little time to do this along with the other assignments but here it goes
I believe this piece to be binary with intro and coda sections.
The intro spans mm. 1-6;
A mm. 7-27;
B mm 28-46;
A’ mm 47-71;
B’ mm 72-83;
and finally coda mm 84-89.
The piece as a whole could be looked at as a tone poem, as with many other Debussy pieces. The first section (intro and A) could very well represent the morning view of the cathedral, shrouded in mist. The second section (B) could be the presence and appearance of the cathedral, and the final section (A’-coda) can show the ocean overwhelming the cathedral as punishment from God for its sins.
Intro/A - mm 1- 27 = section 1, the morning
B - mm 28-46 = section 2, the cathedral
A'/B'/coda - mm 47-89 = section 3, the downfall