The Eiffel Tower, by all means a beautiful landmark, is essentially an enormous drilling rig. Rigs should not be an issue as they are only needed in the initial stages, and a few months for each well. The impact stops when the drilling stops.
Any exploitation of the territory will have an impact on the environment, but there is no doubt that geothermal energy is one of the least polluting forms of energy.
Pipelines can be disguised or buried
Re-injection prevents pollution (thermal or chemical)
A closed geothermal circuit and a closed hot water utility circuit will avoid discharge of waste waters.
The power plants are very low profile, and could be disguised completely by tall trees.