Below are maps of the Lumiose City Boulevards and Avenues/Plazas and the buildings and notable NPCs thereon. Centrico Plaza is omitted because it's dead simple. Distances are not necessarily proportional/to scale.
TODO
Remaining items (whenever I complete the game)
Style increasing events (maybe...)
Color inner streets (maybe...)
North Boulevard
Building 4F: Fighting Dojo/dance studio
3F
Route 13 Gate
Route 14 Gate
Route 16 Gate
^
Building*
Galette Stand
Building
^
Lumiose Museum
Hotel Richissime
Building
^
Battle Institute
Lumiose Station
To South Boulevard <
GS
Cab
GS
Cab
GS
GS
Skater*
GS
Cab
GS
> To South Boulevard
v
v
Café Triste
v
v
v
Pkmn Center
v
Café Ultimo
Café Action
v
Café Bataille
v
v
To Magenta Plaza
Dead end alley
Autumnal Avenue
Dead end alley
To Rouge Plaza
Hibernal Avenue
To Jaune Plaza
Dead end alley
Unnamed street
Inner city
It appears that new Trainers spawn whenever one is defeated (prompted by the player changing branches (Avenue/Plaza)). Which Trainers will appear seems to be random, meaning the same Trainer that was just defeated can reappear immediately.
Only 7 Trainers will be present at the same time in the city (out of the 10 possible total).
North Boulevard branches
South Boulevard branches
Faust
Vacant Storefront
Killian
Aimee
Cass...
Jac...
Sushi High Roller
Kam...
Anais
Trevor 's house
Boutique Couture
Stone Emporium
Café Cyclone
Autumnal Avenue
Poké Ball Boutique
Vernal Avenue
Herboriste
Loto-ID Center
Estival Avenue
Café Rouleau
Lillian
Paget
Magenta Plaza
Café Pokémon-Amie
Rouge Plaza
Restaurant Le Wow
Hibernal Avenue
Café Kizuna
Jaune Plaza
Café Classe
Friseur Furfrou
Bleu Plaza
Restaurant Le Yeah
Café Woof
Lumiose Press
Café Gallant
Lysandre Café
Cab
Juice Shoppe
(Estival Avenue<)
(>Magenta Plaza)
Cab
Toro
Cab
Pkmn Center
North Boulevard branches
South Boulevard branches
Magenta Plaza
Services
Cafés
Autumnal Avenue
Shopping
Fine Dining
Cafés
Rouge Plaza
Facilities
Fine Dining
Hibernal Avenue
Fine Dining
Cafés
Unnamed street
Vernal Avenue
Services
Shopping
Cafés
Estival Avenue
Services
Facilities
Cafés
Café Rouleau
Café Gallant
South Boulevard
Building Pokémon catching researchers
1F
2F
×3 from man 1 on right
×3 from man 2 on right
Route 4 Gate
Route 5 Gate
^
Lumiose Transportation Office
Sycamore Pokémon Lab
PR Video Studio
Building
Building
To North Boulevard <
GS
Cab
GS
GS
GS
GS
Cab
GS
> To North Boulevard
v
Restaurant Le Nah
v
Café Introversion
v
Pokémon Center
v
Coiffure Clips
Café Soleil
Shutterbug Café
v
Blocked alley
To Vert Plaza
Vernal Avenue
To Bleu Plaza
Estival Avenue
Restaurant Le Nah
×15 for perfect meal
Inner city - South only
(These branches are separated out here simply to make them easier to see without the need to scroll horizontally, if so desired.)
South Boulevard branches
Aimee
Cass...
Jac...
Kam...
Boutique Couture
Stone Emporium
Café Cyclone
Vernal Avenue
Herboriste
Loto-ID Center
Estival Avenue
Café Rouleau
Lillian
Paget
Café Classe
Friseur Furfrou
Bleu Plaza
Café Woof
Lumiose Press
Café Gallant
(Unnamed ave.<)
(>Magenta Plaza)
Cab
Toro
Cab