Eurostar London to Paris: booking seats for best views?

There are no real views from the Eurostar train. You're either in a tunnel, or passing by mostly industrial land at 200 km/h. I suppose if you are to pick a side, go with the right side, as that is the side the Eiffel Tower will be on as you approach Paris.

Ah perfect, the kids will be super excited by that. Thanks!

I have never noticed any difference between the views from the two sides of the train.
You do get some nice pieces of countryside, but most of the trip through northern France though rural is flat, just fields.

More important for deciding your seat is what type of seat. If you are a group of 3, 4 or more go for a group of 4 seats surrounding a table (two facing two), then you have your own private family space. And you can stretch your legs without risk of kicking a stranger.
If you are only two, do you prefer two facing seats across a table, or two side.by-side with a table (facing strangers), or two seats side-by-side facing the back of the seats in front (airline style)?

Some first time train travellers get worried about travelling backwards. This is not a problem on a train.
And don't forget to bring your own food and drink for the journey. You can buy this at St Pancras before you go through the ticket barrier.

For more background info see this webpage: https://www.seat61.com/London-to-Paris-by-train.htm
And especially this video with pictures of the seats: https://www.youtube.com/watch?v=l5RAYy9Uymc

I beg to differ about "Some first time train travellers get worried about travelling backwards. This is not a problem on a train." That depends on how badly you are subject to motion sickness.

I rode a commuter train for years (about 1 hour each direction), hoping that the daily exposure would make me build up a tolerance, but that didn't really happen. The few times I got stuck facing backwards I had to cope with pretty heavy nausea and worry about whether I would throw up before we got to my stop.

The first time I rode on a TGV I discovered that motion sickness is worse on high-speed trains because they sort of sway, rather like an airplane that is circling before landing, instead of bumping and jolting along like a regular train.

We took the Eurostar from Paris to London and I did ride backwards with no problem at all. The scenery in France is beautiful with farm land--this was in April and the land was being plowed in the countryside. The tunnel part was about twenty minutes. The English countryside was not attractive in the area the train went through. Scenery most likely will look the same on either side.

If I were you I'd go for the right side (for the Tower) and a "family table" configuration if possible. This means some would be facing backwards. I did this on a different high-speed train and didn't care for it, and I don't normally get motion sickness. It wasn't terrible but it made me uncomfortable. Facing forward lets you see where you're going -- sort of.

In my various Eurostar trips over the years I've never noticed seeing the Eiffel Tower. I wouldn't have been looking for it though, probably getting ready to get off.

I haven't seen the Eiffel Tower from a Eurostar and I very much doubt you can, it is the other side of Paris. I have seen the Sacré-Cœur de Montmartre. You get a brief glimpse of it to the right of the train as you approach Gare du Nord.
It is in the same class as seeing the Channel from the Eurostar (a brief glimpse as you go through the Folkestone Eurotunnel terminal) and seeing Rochester Castle and Cathedral (as you are crossing the Medway Bridge). In all cases you need to be looking in the right direction at the right time, and know what you are looking for.

Thanks everyone! We're booked on the right side, around a table for four plus one across the aisle. We're now locked in for flights, train and accommodations in two cities. The countdown is on!

Good views or not, be sure you study the seating charts so will select a window seat. If you plan to use the metro in Paris you can buy a carnet of metro tickets at the snack bar car on the train. We like to book a carriage at the front of the train or close to it to arrive at the taxi rank and have a shorter wait. The high numbered carriages are at the front of the Eurostar at Gare du Nord, lower numbered carriages are at the front at St. Pancras when you select your seats.

Like Nigel, on my many Eurostar trips over the years, I've never seen the Eiffel Tower -- because it's on a different side of town and you don't come into Paris "sideways," but rather straight from north. I suppose maybe the train conductor (is that what the driver is called???) can see the Tower at some point, but I wouldn't swear even to that.

Chris posted a useful video, shot by The Man in Seat 61 himself. Makes me want to take a train ride. Note the airline-style security check. There's also border procedures inside for France, so arrive well in advance of departure. The Eurostar site has suggestions for how early to arrive. Whether to ride backwards, particularly at high speed, is a knotty issue. Again, Seat 61 provides guidance. But as for a scenic ride, it's mostly about the novelty of the tunnel and what you are going under rather than picture-postcard vistas. To pick up a sandwich and drink for the crossing, there's a Marks & Spencer food shop nearby; here's a map https://www.google.ca/maps/place/M%26S+St+Pancras+Rail+Circle+Simply+Food/@51.5316043,-0.129433,17z/data=!3m1!5s0x48761b3c879aec1d:0xff95595ea7a9c78c!4m12!1m6!3m5!1s0x48761b3c8fd6092d:0xab03c8057ea2a37d!2sSt+Pancras+International+(Stop+S)!8m2!3d51.531601!4d-0.127239!3m4!1s0x48761b3b862474d7:0xc077760b3879d75e!8m2!3d51.5326861!4d-0.1264769