The Allouis transmitter is no longer a broadcast transmitter,
but is still on the air as a time signal station.
Thousands of public clocks, parking meters and so on
are tied to the signal on 162 kHz.
The modulation is just some low phase modulation of the carrier,
that was compatible with the audio broadcasting.
Since the broadcasting ceased, the carrier power has been decreased cautiously.
Also, the weekly maintenance off time has been moved to a day time period.
There are SDR software decoders to read the encoded signals.
Even without that, I could hear 'something' when using SAM on 162 kHz, with the sync demodulator readjusting the phase after each move.
As a LW carrier station, it could be modulated by "Luxembourg" effect at times in some places. If it's in French and not by the RTL station on 234 kHz, then it could be from Algiers on 252 kHz, or from Tangiers on 171 kHz.
Remember that the Europe LW on 183 kHz has been stopped and demolished. The RMC transmitter on 218 kHz is off the air since April 1st, 2020.