A fix for this autogen issue is available since yesterday. Now Orbx and Paris autogen are merged at FSX startup. It works fine with my setup. Sometimes a popup tells you you need to restart FSX to see the merged autogen (in case it changed, because you used FTX Central, or installed a new scenery). Well it's a bit annoying, but it's a really a small price to pay to fly over this wonderful scenery!
Paris scenery with patch v1.05
here. Nord 3400 by Restauravia
here (very convenient to fly low and slow, with a French "Cub" and a French repaint).
As for your missing Eiffel tower, can't tell... It's a default FSX object, so this means it's in "Western Europe" in your base scenery folder (F:\Flight Simulator X\Scenery\EURW\)... Check your scenery.cfg file, maybe EURW is disabled or missing...