My answer is based on numbers I found.
Cipriani Club, 51 active sales listings: $1,551 per ft² (avg)
William Beaver House, 149 active sales listings: $1,644 per ft² (avg)
75 Wall St., 70 active sales listings: $1,340 per ft² (avg)
Downtown Club, 26 active sales listings: $1,143 per ft² (avg)
25 Broad St, 10 active sales listings: $1,130 per ft² (avg)
These are only some of the developments in the Financial District.
While prices per square foot are lower on Battery City, the Common charges are very high.There are 3 new condo developments in Battery City;
Riverhouse, 173 active sales listings: $1,384 per ft² (avg)
The Visionaire, 2 active sales listings: $1,233 per ft² (avg)
Tribeca Green (Rental building), 8 active rentals listings: $7,422 (avg price)

On the contrary, the price per square foot in the Financial District/Lower Manhattan area is much lower than other neighborhoods. While other neighborhoods are able to sell at $1500-$2000 per square foot, the Financial District is averaging about $1100-$1200 per square foot. Battery Park City's average price per square foot is about $1250 for new developments and much less for re-sell properties. $1550 per square foot is an extreme figure and even the most luxurious developments have units that can be purchased for less than $1500 per square foot. When Silverstein completes his Four Seasons at 99 Church, maybe we'll be able to sell at that price point. For now, the Financial District is a great place to call home for a fraction of what you would pay to live in a similar building uptown.

There are 179 new developements in Lower manhattan, 19 in the Financial district area. An average price per square foot in the downtown area is $1,259.00 but the financial district's prices are higher. It's difficult to give you an exact number because when a developement just starts selling, prices are different then when they have sold already more then half. I checked some 6 developments and my average was around $1550 per square foot.
If you want a more detailed number and listings, please contact me at adina.greenberg@cbhk.com