Marklin never made the piezo pantographs available as a spare part that i am aware.

More recent locos have used servos to operate the pantographs.

But I believe your loco is that old that it never had remotely operated pantographs. I don't think they have ever done remote controlled pantographs in an Ae6/6.

I am wondering if a third party manufacturer makes a motorized pantograph that fits Le Capitole M28950.

Hi
I guess, the easier approach is to use a servo motor in the front section of the loco.
The servo must be connected to the pantographs using thin (0.1 mm) nylon wire
The servo can be controlled by a decoder such as ESU suitable for driving 2 to 6 servos depending on type.

Note: I have multiple models using piezo motors (39970 Turmtriebwagen, 46715 Ardeltkran in yellow) and others using Servos (39008 BR 01 with changing level of coal in tender, 39126 BR E10 with motorized pantographs) and the operation is not that reliable (so it may be even worse if you do it yourself). So why why reduce the value of a high prized loco by chages you may regret later

Here is my Turmtriebwagen with its piezo motors
39970 FX Decoder and SDS Drivers.png (1,879kb) downloaded 7 time(s).
They are wearing rapidly (nose in aluminum). Three of them on this model.
Here it is in operation


Cheers
Jean