PRAGUE — A blockbuster bill wending its way through the Czech Parliament would, if passed as envisioned this spring, transact one of the biggest property deals in any former Soviet bloc country by restoring more than half of church property nationalized after the Communists seized power in 1948.

The restitution plan, worth some 134 billion koruna, or about $7 billion, is the most valuable one-time sale of property in the Czech Republic since the fall of Communism in 1989, and it has unlocked a Pandora’s box of historical enmities and social anxieties, prompting Czechs to revisit their strained relationship with the Roman Catholic Church.