I'm just heading back from Paris on one of Eurostar's new trains, wondering why Prince William and Kate chose to fly home, given this Paris to London service is so quick and pain free.

On one side of my carriage are some Welsh rugby fans who have every reason to feel annoyed by France grabbing a last minute victory from the jaws of narrow defeat.

On the other side, a table of passengers who have clearly had too much to drink and yet are still insisting on drinking a lot, lot more.

So for me, a first royal "tour" has just been completed.

My counterparts from other newspapers and broadcasters kept asking me: "how are you finding your first tour?"

The royal couple know how to draw a crowd Credit: PA

And my response was invariably: "I'm fed up of waiting around for hours on end, simply to watch two people leave a building and climb into a car."

And there is so much of that.

Wait around at the Elysée Palace and two people will shake hands with the President and enter a building.

Wait around at the military hospital and two people will eventually emerge from inside and then drive away.

Wait around at the Eiffel Tower and two people will turn up and, you've guessed it, leave again.

It just so happens that those two people are William and Kate, the Duke and Duchess of Cambridge.

Attending a dinner at the British Embassy in Paris Credit: PA

And boy, can those two attract a crowd.

Not just a crowd of press photographers (and there are a lot of those).

But a crowd of internationally diverse tourists who just want a glimpse, a long distance selfie or a quick wave before the couple disappear again.

And it's here that this new royal correspondent began to realise the Royal Family in general, and these young royals in particular, are the correct definition of international superstars.

So are they just waving, smiling crowd-magnets?

Or something more than that?

Prince William delivering a speech during a reception dubbed Les Voisins (The Neighbours) Credit: PA

The whole point of this tour (if two days counts as a 'tour') was to soften relations, to strengthen ties and to press the flesh ahead of Brexit.

William and Kate hosted a dinner to launch a campaign called 'Les Voisins' ('Neighbours' in English) which will build on the cultural and sporting ties between Britain and France.

And on that particular evening, we were ten days away from Theresa May triggering the UK's divorce the the EU?

So just ahead of it, the Foreign Office had dispatched Wills and Kate on a European charm offensive with a meeting with President Holland and a full time reception and dinner at the British Embassy.

Safe to say, that part of the tour was 'mission accomplished'.

The Duke and Duchess meet Jessica Bambal Akan Credit: PA

And then there was the wounded and the traumatised that the Duke and Duchess met at Les Invalides military hospital.

Like Jessica Bambal Akan.

She was shot 7 times during the terror attacks at the Bataclan theatre in 2015.

She spoke to the royal couple about her ordeal, her injuries and the new zest for life she has found since her brush with death.

If this visit achieved nothing more than to remind us all of those who died (130) and those who were injured that night (some 400) then it was well worth it.

And this conversation between survivors and royals took place just as France was dealing with yet another terror strike a short distance away at Paris' Orly Airport.

Prince William is the new patron of the Welsh Rugby Union Credit: AP

What you notice about these trips is the detailed attention to planning: where they go, what time they arrive, who they meet, where they stand.

But there are some things that are beyond the control of even the most meticulous of royal planners.

Like the win that Wales was on course to achieve in the final minutes of their Six Nations Rugby match against France.

Prince William is the new patron of the Welsh Rugby Union.

And you don't have to look too far on social media to find those who make the accusation that this whole trip was organised to justify an afternoon at the Stade de France.

The royals were disappointed to see Wales lose Credit: PA

But if the Duke had brought with him some luck for the Welsh team, it ran out at the very, very end.

And France ended up the victors just when most fans in the stadium thought that the hosts had actually lost.

So, like the rugby fans on my train, William and Kate returned home disappointed.

But this is the first of six EU countries which will receive a royal visit over the next few months (Prince Charles and Camilla cross off three more in March and April).

And the Royal diplomatic tour of Europe will go on.

I just hope there will be less waiting around on the next one.