Article 198 mandates that all industrial entities whose exemptions were protected by Article 197 must start filing tax returns immediately after their holiday ends. The first return must be filed for the tax year following the final year of the exemption period. This return, along with audited accounts and the tax due, must comply with all standard procedural and payment rules (Articles 134-150). Failure to transition into the filing regime on time can lead to fines under Article 179, ensuring these previously untaxed entities are correctly integrated into the tax system as soon as their incentive period concludes.