I disagree with that, there's enough places around Paris that are good-looking or relaxing that I don't feel the need to leave Paris on the week-end (at random: Paris Observatory park in Meudon, with a great view on Paris)
Perhaps it's just because I've grown up in the UK, surrounded by gothic and medievel buildings etc so a lot of Paris is just more of the same, but for me my weekend trip to Paris about 10 years ago ranks at the bottom of all my holidays. I found Berlin far more interesting and exciting than Paris. There are some lovely bits of Paris, but huge swathes of it are traffic stuffed concrete ovens during the summer. The Arc de Triomphe is surrounded by a 6 lane roundabout, which is fun to watch for a bit, but rather detracts from the ambiance of the site.
It's good for 5 minutes, or to see it once in your life, but it's one of the worst place to appreciate Paris / London.