Short description:
D. CONSTANTI - NOPOLIS². Constantinopolis, helmeted, mantled bust left, sceptre over shoulder.
R. Victory on prow, standing facing, head left, holding transverse sceptre and resting left hand on shield³. R Ɛ⁴, in exergue.

The search on the web for coins of the type of figure gave rise to the following results:

1. https://www.acsearch.info/search.html?id=2087809 London Ancient Coins Ltd http://www.lacoins.co.uk/ Auction O 283 24.07.2014 Description: Commemorative series, c. 330-354. Æ (17mm, 2.73g, 6h). Rome, c. 333-5. Helmeted and mantled bust of Constantinople l., holding sceptre. R/ Victory standing facing, head l., holding sceptre and round shield, with foot on prow to l.; R-wreath-E. RIC VII 355. Green patina, VF.
2. https://www.wildwinds.com/coins/ric/city_commemoratives/_rome_RIC_VII_355.jpg City Commemorative, AE Follis. 333-335 AD. Rome. 18mm, 2.18g. CONSTAN-TINOPOLIS, helmeted, mantled bust left, sceptre over shoulder. Victory on prow, standing facing, head left, holding transverse sceptre and resting left hand on shield. Mintmark: R wreath epsilon. RIC VII Rome 355; Sear 16465. Rated Scarce. Contributed by Den of Antiquity (ebay: denant), Oct. 2012.
3. https://www.acsearch.info/search.html?id=2749748 London Ancient CoinsLtd http://www.lacoins.co.uk/ Guttus Auction 12 205 20.11.2015 Description: Commemorative series, c. 330-354. Æ (16mm, 1.84g, 6h). Rome, c. 333-5. Helmeted and mantled bust of Constantinople l., holding sceptre. R/ Victory standing facing, head l., holding sceptre and round shield, with foot on prow to l.; R-wreath-E. RIC VII 355. Green patina, near VF.

Regards.
Giulio De Florio

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Note:

(1) The physical characteristics of folles from the links above are shown below::

Fonte	Peso (g.)	Diametro (mm)	di conio (h)
Link1	2,73	17	6
Link2	2,18	18	-
Link3	1,84	16	6

The data in the table cannot be compared with those of the figure coin.
(2) CONSTANTI - NOPOLIS. The following considerations are taken from a study by Salvatore Calderone, entitled Constantinople: "the second Rome", constituting a chapter of the treatise "History of Rome", ed. Giulio Einaudi 1993. On July 25, 326AD, at the end of a visit to Italy, Constantine I stopped in Rome to close the celebrations related to his twentieth year of reign (just to recall Constantius I, his father, on his deathbed, on the same day, twenty years earlier, in the presence of the notables of the kingdom, had conferred upon him the imperium). And there, in the capital of the Roman Empire, with great scandal of the conservative pagan circles and great resentment of the people of Rome, he had refused to make, together with the army, the traditional sacrifice in the temple of Jupiter Capitoline. Then he turned his back on the eternal city to never return. The outrage had not been accidental. The Constantinian design had as an objective the religious and political rebirth of the entire Roman world, the creation of a bridge between the West and the East recently unified after Licinius' defeat. And the symbolic place of rebirth could not be the city of the decrepit senators, but it had to be a new and large city to be built in a central position with respect to an empire that extended from the Atlantic Ocean to the Euphrates, from the Danube to the Egypt. God in person, appeared to him in a dream, had indicated to him a few months earlier the place of the ideal city: Byzantium, the ancient Greek city on the Bosphorus. Therefore Constantine, in adherence to Roman sacred law, in the guise of a magistrate with an "imperium", accompanied by Pontifex and Augure (the pagans Praetextatus and Sopratus respectively), spear in hand, had traced the perimeter of the new city, eight times larger than old Byzantium. The forms of Roman law were not for Constantine irreconcilable with those of the Christian religion because the sign expected at the foundation was represented by the divine will that had preceded and accompanied the event! May 11, 330 had been a day of great celebration for the inauguration ("consecratio") of the city which had been equipped with mighty walls and which, some time before, had assumed the name of Constantinople, if it is true that from there, not from Byzantium, some of the constitutions that have come down to us are dated. A couple of years later, on an unspecified date between 332 and 333, a law was passed that gave the city the legal status of "second Rome", second only in a temporal sense, but new, regenerated, compared to the first, capable of initiating a historical cycle of renewal, the rebirth of the Roman world, with Christian ideology assuming a polical role. The new status of the city had also practical consequences, such as the free distribution of grain to citizens (attested for the first time on 18.5.332, as Chronicon Paschale reports), similar to that granted to Rome for centuries, or fiscal and civil privileges granted to sailors of the East for the transport of wheat destined to the city.
(3) In order to commemorate the consecration of the city of Constantinople two coins were ordered:

1. one, CONSTANTINOPOLIS on the obverse and Victory on prow on the reverse, in memory of the naval victory gained by Crispus over Licinius (RIC VII 355 - see, for example, the link);
2. the other, VRBS ROMA on the obverse and a she-wolf suckling the twins (RIC VII 354 - see, for example, the link).

(4) R Ɛ is the mint sign, formed by the letter R, short for "Rome", a wreath, characteristic symbol of the period 333-335, and the letter Ɛ (number five in Greek) which designates the fifth of five workshops active at the time in Rome.