False declaration triggers notice and reassessment under tax compliance scheme, with penalties and potential penal proceedings. The Commissioner may serve a show-cause notice where he records reasons to believe a declaration under the Scheme was false in material particulars, subject to a one-year limitation. If satisfied the declaration was substantially false, he shall, within a prescribed short period after notice, assess tax and levy penalty as if no declaration had been made, allowing credit for tax paid under the Scheme, and may initiate proceedings for furnishing a false declaration.