The fight to take over Market District (District Showdown) will be possible only after D.U.P. forces control less than 30% of a district. Go to the place marked with a phone icon (large billboard on the rooftop) and make a call.
The biggest threat is a new type of elite opponents - they have more powerful powers than usually. I recommend fighting with them on the rooftops or on the highway located over the previously destroyed mobile command centre.
Rewards for taking over Market District to:
- Unlocking fast travel
- Getting rid of all D.U.P. soldiers in the area
- Unlocking Delsin's unique clothes - Loaded