Connecting through Frankfurt

Did you book your entire journey through one ticket/purchase? If so your mostly likely just changing gates. As long your scheduled gate is not changed due an unforeseen problem causing an arrival gate to change and be at another terminal it should be a breeze. I usually look at the airport website to see what area the overseas flights on your carrier land at and look at what area the European flights on your carrier usually depart from. Regardless, the German's are very efficient and an hour and 45 minutes should be plenty of time. If you purchased two flights you would need to collect your bags and recheck them and go back thru security which would scare me with less than two hours. J

You will have to go thru passport control in Frankfurt as that will be your entrance to Schengen.
If this is all on one airline the airlines are pretty good at ushering you thru so you’ll make your flight
Make sure your bags are checked thru to Venice

Depends on the customs lines, but 1 hr 45 should be ample.

We did a 1 hour turnaround in March, RAN through the airport and were scolded when we got to our departure gate. Wouldn’t recommend repeating that.

The real hang-up was a 20 to 25 minute wait to clear customs.

Late edit
RIGHT, Christine - Passport control

Fred is referring to Immigration or Passport Control

You don’t go thru Customs until your final destination in Venice- it is nothing more than walking thru a door

As others have mentioned, you shouldn't have to exit security, but you will need to go through passport control. Usually not terrible in Frankfurt, but I've had a couple times where it was a little slow.

I typically allow at least 2 hours when making an international connection like this to accommodate late arrivals, I typically prefer 3 hours and have never missed a connection other than due to canceled flights in 30 years of business travel to Europe. But an hour and a half should probably be ok at Frankfurt unless something is really wrong or messed up.

The caveat is that if you are transferring to/from airline that doesn't have baggage transfer agreements (and you are checking bags) then you have to collect your bags which is outside of security, forcing you to go through the re-entry process. This wouldn't be the case with typical tier one airlines eg. American, British Airways, Lufthansa,Delta and etc.. It is usually a case when you are are dealing with an LCC or ULCC type airline (Ryan Air, Wizz, Easy Jet and etc.) often don't have baggage transfer agreements. Thus you have to collect your bags if checking and deal with that. So be aware.

You do not say your expected arrival time or airline, but assuming it is Air Canada with partner Lufthansa to Venice, there are 4 nonstops a day from Frankfurt, 8:35 am, 12:35 pm, 4:30 pm, 9:00 pm. Thus if you are late inbound, there is a very good chance they will get you on the next flight.

Flown via FRA many times, including this past weekend.

I'm assuming you arrive from Montreal (YUL) at 7:05 (LH479/AC9634) and depart to VCE at 8:50 (LH324/AC9310), both operated by Lufthansa.

Your arrival gate will be one of the Z gates, while your departure gates will be one of the A gates.

It seems like a lot, but be aware that T1 pier A/Z has 2 levels. The Z gates are directly above the A gates, therefore, for example, gate Z69 is directly above gate A69. Z levels handles extra-Europe Schengen flights, while A level is for European flights.

If you are lucky and for example the plane arrives at Z50 and the departure to VCE is at A50, then it is a simple short walk to passport control (which is near Z50) then the escalator down to the level A. But if you are not so lucky and for example you arrive at Z69 and depart from A40, which are at the opposite ends of the T1, not only do you have to go to the A gates below, but basically you have to walk from one end to the other of the T1, and that walk is about 1 mile (T1 is nearly one mile long, albeit there are moving walkways).

This weekend, to return to SFO, my arrival gate was A20 or 21 (don't recall) and my departure to SFO was Z69, so I had to walk nearly 1 km (besides going up the escalator). I only had 15 min from arrival to start of boarding, so had to walk really fast but made it.

The line at passport control varies, fortunately I'm dual citizen, so the passage for EU citizen has no line and the passport (and your face) is scanned electronically only (no interaction with agents) so it's just seconds for me or my wife. If you hold only Canadian citizenship then there will be a line, but generally it's not overly long. The long part is (potentially) the walk, depending on the Z gate number of arrival and the A gate number of departure (and viceversa when you go back home). There will be no additional security check, only passport control.

The other issue is that FRA air traffic has exceeded is capacity, and the brand new huge T3 is still under construction. That means that there is a high chance (if you travel in high tourist season) that your plane (on arrival and/or departure) will not dock to the Terminal gate, but rather it will park at an apron position far away in the tarmac, and therefore they will take you to the Terminal arrival gate on a bus after you descend the plane. The deplaning via bus takes some extra time as the plane may be parked a bit of a distance from the terminal. In my case this past Saturday, both my arrival plane (from LIS) and my departure plane (to San Francisco) had an apron docking, which meant having to be bussed from the gate to the plane far in the tarmac.