310. The chair of the Priest Celebrant must signify his function of presiding over the gathering and of directing the prayer. Thus the more suitable place for the chair is facing the people at the head of the sanctuary, unless the design of the building or other features prevent this: as, for example, if on account of too great a distance, communication between the Priest and the congregation would be difficult, or if the tabernacle were to be positioned in the center behind the altar. In any case, any appearance of a throne is to be avoided.[Inter Oecumenici 92] It is appropriate that before being put into liturgical use, the chair be blessed according to the rite described in the Roman Ritual.[Book of Blessings 880-899]
No throne-like appearance. Hmm, a challenge in some places, perhaps in a few cathedrals.
Likewise, seats should be arranged in the sanctuary for concelebrating Priests as well as for Priests who are present at the celebration in choir dress but without concelebrating.
The seat for the Deacon should be placed near that of the celebrant. For the other ministers seats should be arranged so that they are clearly distinguishable from seats for the clergy and so that the ministers are easily able to carry out the function entrusted to them.[Inter Oecumenici 92]
Most liturgists prefer other ministers to be less distinct from the assembly. One challenge I’ve seen in many places are when chairs for altar servers would be used where concelebrating clergy would sit.