After you reach Parfum Palace, you can enter Palais Lane from the east side to reach a previously inaccessible area.
Battle and Catch
In the tall grass, you can encounter Kecleon, Honedge, Oddish, Espurr, Nincada, and Sentret.
Just southwest of where you enter the east side of Palais Lane, Backpacker Jerome is in the grass. He has a level 14 Fletchling.
East of Backpacker Jerome, there is an Antidote.
Southwest of Backpacker Jerome, there is an X Speed.
To the south, you can find Tourist Mari. She has a level 14 Illumise.
East of Tourist Mari, Tourist Takemi is in the grass. He has a level 14 Volbeat.
East of Tourist Takemi, you can go east through the grass, then north, and find a hidden Tiny Mushroom in the middle of the slope up above.
South of there, you can find a Paralyze Heal.
South of there, you find Youngster Jacob. He has a level 11 Croagunk and a level 13 Beedrill.
In the southwest of the east side of Palais Lane, you can find TM09 Venoshock.