That Shall We Kiss? is such a breeze is just one of its complicated tricks. French writer/director/star Emmanuel Mouret’s tale of domestic deception and decency is so streamlined, so unfailingly sympathetic to all involved, it’s not until its conclusion that you whiff the careful measure of reassurance, doubt and resignation Mouret has laced through it.

It barely strays from its simple through-line: what appears to be an extra-marital tryst in-the-making unfolds into a life lesson as Émilie (Julie Gayet) tells Gabriel (Michaël Cohen) — a cool and kindly stranger she meets on the street and is drawn to enough that she agrees to get a drink with him — a cautionary story about how an attempt at kindness unravelled the love lives of some friends of hers. Then, through flashback, we meet Judith (Virginie Ledoyen) and Nicolas (Mouret), best friends since high school chilled by the sudden discovery that they are, at long last, star-crossed lovers — very much in spite of the fact that Judith is (was) happily married to a terrific fellow already.

The couple’s progressive attempts to fight their instincts, satiate their lust, embrace their shame and confront fate is rendered, somehow, as black and sweet as molasses. Their bumbling and running commentary, explaining their actions to themselves — and us — keeps them just north of decent while Mouret fleshes out his love-hurts affirmation. It’s a subtle seduction, but in the end we see love and loyalty as clearly as Mouret does: natural, fraught and — if handled with care — wonderful.