When we did the trip last month, we flew Air France and had our connections in CDG for our flights into Rome and out of Venice.
In both instances you had to go from one terminal to another. 2E to 2F if memory serves.
In order to do this, you take a shuttle bus.
You also walk down and around and up and down and around again in the process.
Also, you WILL have to go through passport control and a security check point.
I wouldn't want to have any less time than 2 hours between flights.
A slight delay in your arriving flight could become very stressful
Oh, BTW on our flight into CDG from NY, they didn't have a gate available and we disembarked via a stairway and then had to take a shuttle bus to the main shuttle bus... They have a lot of those stair thingings all over the place, so my assumption is that this is a common occurrence
Also, just an FYI... The Venice airport is crazy crowded when you first get there. The check in counters don't open until 2 hours before scheduled flights, this is for all airlines. While tourist travel has increased, the area at the check in counter and security has not. It is truly "cattle call" time.
Once you get through security the airport itself is beautiful at the gate areas.
ABD will have your water taxi scheduled to pick you up approx. 3 hours before your flight !!!
Trust me .... You'll need it