Flue Pipe Would It Cause A Problem If We Connect A 6" Pipe (of Wood Stove) Into The 7" Steel-lined Flue?

Would it cause a problem if we connect a 6" pipe (of wood stove) into the 7" steel-lined flue? - flue pipe

I know we can make an adapter to get in touch, but I wonder if the exhaust is another project also Stong? No other device connected to the fireplace and the stove is a waterproof model.