So, here is a Deepl translation of the solution 
It’s quite a Sioux-like trick… Cuckoo’s video put me on the right track (Sioux…), but I’m mainly exploring the theme of synchronisation and tempo.
Basically, what we’re going to do is send CV signals from the Octatrack to the Pulsar. You might say: ‘That bloke’s mad – the OT doesn’t have a CV function!’ That’s true, but the Sioux always have more than one trick up their sleeve. So we’re going to use audio CV.
First thing to do: synchronise the Octatrack properly with the Pulsar. To do this, you need to untick the ‘send’ box for the Octatrack’s MIDI clock, because otherwise the OT constantly sends a MIDI clock signal, which the Pulsar doesn’t like. From then on, there’s no longer any MIDI synchronisation between the two units, but the Pulsar does receive the start/stop signals from the OT, which is handy.
Next, connect the Pulsar’s clock output to one of the six 1/4-inch jack sockets and route the audio signal from the Pulsar’s corresponding audio output to one of the Octatrack’s inputs. Record the clock signal into the Octatrack for the entire duration of the sample. Then, save this sample after normalising it.
Next, place it on any track but set it to CUE output, at the track’s maximum volume. Turn off the CUE on your headphones (otherwise, you’re guaranteed to blow a fuse). Next, feed this audio into any input on the Pulsar, and retrieve the signal via one of the six corresponding 1/4-inch jack pins. Using an alligator clip, connect this pin to the Pulsar’s clock In (the same pin used to record the CV clock audio).
Set the MIDI/IN switch to the middle position: at this stage, the Pulsar is neither connected via MIDI for synchronisation nor operating in standalone mode. Instead, it synchronises to a CV signal, simulated here by the audio recorded on the OT.
Next, on the OT, insert an audio trigger on the track containing the recorded clock audio, with a time offset of 1/96 to the right. Copy this trigger and paste it onto every position in the OT sequence.
Don’t forget to connect pin 0.25 of the clock divider to the LRST pin, to ensure synchronisation between the looper and the clock divider.
And there you have it: the OT now sends a CV signal recognisable by the Pulsar, which synchronises perfectly with it. Love, always!
From there, you benefit from the Pulsar’s improvisation capabilities, MIDI synchronisation and effective tempo locking, so you can play samples live, perfectly in sync with the Pulsar’s beat. What’s more, if you want, you can add a MIDI track on the OT and make use of the conditional triggers. Finally, you can also patch the Pulsar as usual and thus use the Pulse Converter. All this without spending a single euro and without any additional kit.