This story is unashamed romanticism. The Doctor and Rose having dinner and a dance in a beautiful setting.
In the 2006 
Doctor
Who Annual (published for the 2005 Christmas market) Russell T. Davies
wrote a short biography of Rose before she met The Doctor which had her
visiting Paris with Jimmy Stone, the boy she left school without doing
her o’levels for. That came out after I wrote
Parisian Interlude in the summer of 2005 and in any case does not preclude
a desire to go there for her 21st birthday. In any case, The
Doctor takes her to Paris in a style no ordinary boyfriend ever could.
One question I have been asked and can’t answer, is WHY was the Prince of Wales, the heir to the British Crown, guest of honour at the opening of a monument that celebrated the centenary of the French getting rid of their monarchy. And I have never been able to find out. But it was not a mistake. He WAS the guest of honour. There was a reception on the mezzanine floor, a royal trip to the top of the tower and dinner and dancing followed by fireworks. And yes, it is a matter of historical fact that Albert Edward, Prince of Wales, later King Edward VII, was a ladies man. Rose was right to want to keep The Doctor between him and her.
The Lord du Temps, of course, is French for Time Lord – more or less!
Incidentally, this story went through several rewrites due to trying to establish exactly when Rose’s birthday really was. Again the 2006 Annual settled that when Russell included the date, April 27th.
And yes, the lifts were from the Otis company
of
The necklace that The Doctor gives Rose as her birthday gift is, of course, inspired by the TARDIS key which was seen in some earlier episodes of the series which had the six stars of the Kasterborus constellation on one side and a geometric design representing the same on the other. This family heirloom comes into several later stories as Rose wears it all the time from there on.
http://www.en.wikipedia.org/wiki/Eiffel_Tower
http://www.pbs.org/wgbh/buildingbig/wonder/structure/eiffel_tower.html
http://ssa.paris.online.fr/pages/7th.htm
http://park.org/Pavilions/WorldExpositions/paris2.text.html
