You can do a couple of things. A Realtor will be able to tell you the estimated tax's on a current property. Or you contact the City of Grosse Pointe Park at 313-822-6200 or go to GPP's municipality website to get access to the city clerk.
you can find the tax rates and estimated annual property tax rates at the State of Michigan Treasury Department website. It can be a little difficult to find the Property Tax Estimator on that site so I have a link to it on my website at http://www.MInextHome.com The link can be found under the heading "For Buyers".