The Indian Contract Act, 1872
168. Right to finder of goods may sue for specified reward offered –
The finder of goods has no right to use the owner for compensation for trouble and expense, voluntary incurred by him to preserve the goods and to find out the owner; but he may retain the goods again the owner until he receive such compensation; and where the owner has offered a specific required for the return of goods lost, the finder may sue for such reward, and may retain the goods until he received it.