In 1841–42 he undertook a diplomatic and exploratory mission to the regency of Tunis, which was seeking French protection from the Turks In 1844–45 he travelled in Egypt to obtain information about the proposed Suez Canal, and returned via Palestine, Syria and Turkey.

[1] His parents were Ildephonse Plichon (1773–1855), a merchant and then manufacturer of salts and soaps, and Joséphine Bénédictine Leclercq (1772–1835).

When that movement's leader, Barthélemy Prosper Enfantin, added religion to the Saint-Simonian economic doctrine, Plichon accepted the new pantheism.

[3] In 1841 Ahmed Bey of Tunis was concerned that the Sultan of Constantinople, theoretically his sovereign, was planning to send a fleet to obtain the tribute that was owed to him.

[5] France did not want the Turks to threaten Algeria, which they had decided to fully occupy, so sent a naval division to La Goulette, the port of Tunis.

[5][a] Plichon, a young man with no diplomatic experience, was to cross the great tract of desert between the two cities.

[5] He sailed to Tripoli where he learned about the local political situation from Captain Bailleul, head of the French military mission, then set out on the hazardous land journey from Tripoli to Tunis along the coast, passing through no man's land between the last Turkish outpost of Zuwarah and the Gulf of Gabès.

[7] His lengthy report discussed the history of the regency, once prosperous from piracy, now constrained by the French and British, and suffering from revolts in the south.

Plichon provided many statistics on the Tunisian finances, army and tribal forces, and advocated the same expansive colonial policy as in Algeria.

Enfantin, with support from François Barthélemy Arlès-Dufour, a Saint-Simonian financier of Lyon, was dreaming of creating a great railway network in France.

There he was welcomed by Saint-Simonians such as the engineer Charles Lambert, the doctor Nicolas Perron, and Linant de Bellefonds, author of a detailed study of projects to pierce the Isthmus of Suez.

The 800 electors of the Hazebrouck constituency were more interested in Rothschild's planned railway network than in the dynastic question, and wanted their city to be the intersection between the Paris–Calais and Lille–Dunkirk main lines.

[12] Helped by Guizot, who wanted to reduce the influence of the loyalists in the Nord, Plichon achieved good results and became popular.

[3][b] Some thought that Plichon was the spokesperson for the "grande famille" of landowners in the Nord region, the intermarried Cleenwerck, Vandewalle, Bieswal and de Coussemacker families.

[11] In 1860 he protested the invasions of Piedmont in such strong terms that the president of the Chamber, Charles de Morny, withdrew his speech.

[3] He criticized the inconsistency of Napoleon III's policies, saying "One cannot be revolutionary in Italy and remain conservative in France and Rome.

[16] Adeline's uncle was Symphorien Boittelle, a very energetic prefect of the Paris police from 1858 to 1866, deputy for the Nord until 1863, and Senator from 1866.

[15] In 1862 Plichon spoke of the revival of socialism, saying a "certain press was responsible" while the Catholic journals had to remain silent.

[1] Under the French Third Republic Ignace Plichon was a member of the National Legislature and then the Chamber of Deputies for Nord from 8 February 1871 to 3 June 1888, representing the Union des Droites.

[19] He was president of the Mines de Béthune administrative council from 1873 to 1883, when he resigned, apparently due to a conflict with his father in law Bouitelle.

The company faced many difficulties during his term of office, and had only moderate growth, since neither Plichon nor Boitelle had technical training.