I love this spread - use it regularly with the Tarot de Marseille. Mary Greer had a lengthy description of the spread on her blog about a year ago. Just as nearly every book and LWB in English has the Celtic Cross spread, every book I've ever seen in French or Italian has this spread.
I believe it was Oswald Wirth who used the metaphor of a courtroom for this spread. Cards 1 and 2 are attorneys arguing for and against the issue at hand, and card 3 is the judge sitting above everyone else mediating between the two arguments, or giving a more objective viewpoint of the issue. In card 4 the judge issues his pronouncement - what must be done, or what the near future looks like.
I'm one of the few TdM readers who actually likes the un-illustrated pip cards. I often use just the suit cards for the first 4 spread positions, add them up and put the corresponding trump card in the middle for card 5. As the only trump, it really stands out as the most important card in the spread.
As Kwaw pointed out, the laws of mathematics skew the results when you add up the sum of the first four cards and reduce the number to something 22 or below. But there doesn't seem to be anything you can do about it, except be aware that certain trump cards will appear very rarely, or not at all.
There's the question of what numbers to assign to the court cards when adding up the sum of the cards. I originally assigned 2, 3, 4 and 5 to the court ranks because it felt intuitively right. Then I found out these are the values assigned to them when playing the game and adding up the points in your hand. I think any system works as long as you believe in it and use it consistently.
Thanks, Pam O, for reviving this classic spread. I think it deserves to be better known in the English-speaking world.