Most listings are in the $20's per square foot per year. The Franklin Park region is experiencing a an increase in rates. In the last 3 months, the median rate went up $27 per sqft per year.
In the last 90 days, 1 listings have been posted online, which means leases most likley are going fast. You'll want to be prepared to make an offer immediately. About 200% of the available space in the Franklin Park are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,550 sqft. Most buildings in this region were built in 1999 and are Class A.