The exact game system.
This is still one of the points to be determined for the staff of Mauricio Pochettino, on the eve of the shock of the quarter-finals of the Champions League between Bayern Munich and PSG.
A 4-2-3-1, the Argentine's favorite pattern since his arrival, or a more classic 4-3-3 in recent seasons in Paris?
The answer to this question will give one more clue as to the eleven chosen by the Parisian technical staff.
This Tuesday at the Allianz-Arena in Munich, like Monday morning at the Camp des Loges, Pochettino did not make any tactical set-up.
On the Bavarian lawn, his players were treated to 6 against 6 oppositions with four substitutes on each side, entering at the request of the Argentinian assistants.
Before the start of this hour-long session, the young Ismaël Gharbi (16), summoned as Kenny Nagera (19) or Abdoulaye Kamara (16), was entitled to a friendly slap from Pochettino.
But the collective session gives no clue about the more precise wishes of the former Tottenham coach.
The most logical would be to see him renew the eleven aligned against Lille last Saturday (0-1) with a change between Leandro Paredes (suspended) and the returning Danilo Pereira in the middle.
If, however, the temptation to strengthen the midfield is present at Pochettino, Angel Di Maria could give way to Julian Draxler, Rafinha or Ander Herrera.
Even if this last option seems not very credible in view of the low playing time of the Basque for a month.