Psalmody Antibes style

Just round the corner from our house, just beyond the Archives Municipales, there is a nondescript house with an arched doorway. There are many of these arches in Antibes, and this one didn't look too special. However, when the sun slants across the limestone at the right angle, shallow, crude epigraphy reveals itself.

The spelling is barbarous, and this is what I think it ought to be saying, corrected, in rhyme:

Ecce quam bonum
Et quam iocundum
Habitare fratres in unum

Oh how nice, and oh how jolly, that the brothers live together

Trite, until you realise it is a quote from Psalm 132 (133), often set to music during the reign of François 1er, and certainly sung by Savonarola's supporters during their holy hooliganism. Not an innocent text. So perhaps a more appropriate biblical rendering is in order:

Behold how good and joyful it is for brothers to live in unity.

By the way, there appears to be a date on the chamfered underside of the lintel. Can anybody decipher it?