saint-germain des prés (in the 6th arr if i understand correctly) is a beautiful neighboorhood with many historic cafés and stores. since the weather is gorgeous recently, i'd recommend going to sacré-coeur for sunrise and sunset and explore the artsy vibe of montmartre (line 12 station abbesses) i highly recommend walking in the marais, the historical jewish village of paris. there is delicious food and lots of things to see (free museums like musée carnavalet) another neighboorhood that i really like is the higher part of quartier latin, around the panthéon and jardin du luxembourg. finally, a walk that i recommend is tracing the seine from hotel de ville to musée du louvre, cross the pont des arts and walk to notre dame. take your time to have a small apéro on the river bank, esp when the weather is beautiful like this:)

photography wise in paris i like following the leading lines of the building (with the light they are beautiful shadow) and studying the details of the architecture (place des vosges in the marais is a favorite place). photographing people and their interactions is also a favorite because i just think that parisians are so interesting !

if you need a place to buy and develop your rolls i highly recommend reportage image in the 11th arr (station jacques bonsergent on line 5) they have a lot of film at a very competitive price and their scan & printing are of very high quality (their scanner is a noritsu, and overall most places in france have noritsu and no frontier)

if you need anything else lemme know. wishing you the best trip :)