Chasing Tifa and To Corneo's Mansion are quests in Chapter 9, "The Town That Never Sleeps", in Final Fantasy VII Remake. They take place in the Sector 6 Slums and Wall Market. As Cloud Strife and Aerith Gainsborough are about to part ways, Cloud sees Tifa Lockhart in a carriage, and Aerith encourages him to follow her and help her.
Follow the linear path to a stablehand and talk to him. After a cutscene, when Chocobo Sam asks about Tifa Lockhart, the player can select "She's in great shape", "She's a great fighter", or "She's good at handling the books". The choice will affect which questline for sidequests takes place during the chapter. Any option will proceed the cutscene, after which the two will have no leads other than Corneo's mansion.
Travel north to end up in Wall Market. The disc "Under the Rotting Pizza" can be obtained in the southern area, "Honeybee Inn" can be purchased from the item store, and the disc "Farm Boy" can be obtained in a house on the upper level in the northwest area. Chadley can also be spoken to for Battle Intel updates as well as the chance to fight Fat Chocobo to obtain the Fat Chocobo Materia. Fat Chocobo is a fairly basic boss with strong melee attacks and can summon smaller enemies; avoid its attacks, defeat the enemies it summons and try to stagger it with magic spells to deal most damage. Purchase any new materia available from Chadley. At the weapons vendor in the south, Cloud can purchase the Hardedge weapon, and previously available armor and some new accessories. A Barrier Materia is found down an alley in the western end of the Wall Market, and a headband accessory ( Sleep protection) in the gym's shower room. There is also a treasure for adrenaline in the inn and a treasure for celeris atop the junk further on from the jukebox area (up the stairs) .
To proceed with the quest, head to Don Corneo's mansion in the south end of Wall Market. Johnny dashes through Wall Market on the way there, commencing "Vagabond Johnny". After this detour, continue south and enter the mansion. After talking to Leslie, this leads to the next quest, "The Trio".